Display panel and manufacturing method thereof, alignment method

ABSTRACT

A display panel and a manufacturing method thereof, and an alignment method are provided. The display panel includes a display substrate and a cover plate connected through an optical adhesive layer. The display substrate includes a plurality of light emitting elements, a pixel defining layer, and an encapsulation layer; the encapsulation layer includes a first inorganic encapsulation layer, a first organic encapsulation layer, and a second inorganic encapsulation layer; the display panel includes a display region and a frame region including a cutting region and a dam glue region where a dam glue is located; at least one of the plurality of cover plate alignment marks is between the dam glue and the display region and is overlapped with the second inorganic encapsulation layer, and at least one of the plurality of cover plate alignment marks is between the dam glue and the cutting region.

TECHNICAL FIELD

Embodiments of the present disclosure relates to a display panel and amanufacturing method thereof, and an alignment method.

BACKGROUND

Organic light emitting diode (OLED) display devices are new displaydevices, which have many advantages, such as active light emission, highcontrast, fast response speed, lightness, and flexibility.

Touch screens are more and more widely used in various portable devicesbecause of advantages such as robustness, fast response, space saving,and convenient communication. It is foreseeable that a touch-sensitiveOLED display device obtained by integrating a touch screen and an OLEDdisplay device will become the mainstream of the market.

SUMMARY

Embodiments of the present disclosure provide a display panel, whichcomprises a display substrate, an optical adhesive layer, and a coverplate. The display substrate comprises a flexible base substrate andcomprises a plurality of light emitting elements, a pixel defininglayer, and an encapsulation layer, in which the plurality of lightemitting elements, the pixel defining layer, and the encapsulation layerare on the base substrate, the pixel defining layer separates theplurality of light emitting elements, and the encapsulation layer is ona side of the plurality of light emitting elements away from the basesubstrate; the optical adhesive layer is on a side of the encapsulationlayer away from the base substrate; and the cover plate is on a side ofthe optical adhesive layer away from the display substrate and connectedwith the display substrate through the optical adhesive layer. Thedisplay panel comprises a display region and a frame region at aperiphery of the display region; the frame region comprises a dam glueregion where an annular dam glue is located and an annular cuttingregion which is on a side of the dam glue away from the display region;the encapsulation layer comprises a first inorganic encapsulation layer,a first organic encapsulation layer, and a second inorganicencapsulation layer which are sequentially arranged in a direction awayfrom the base substrate; the display substrate further comprises aplurality of cover plate alignment marks configured for aligning thedisplay substrate with the cover plate; and at least one of theplurality of cover plate alignment marks is overlapped with the secondinorganic encapsulation layer in a direction perpendicular to the basesubstrate, and an orthographic projection of the at least one of theplurality of cover plate alignment marks on the base substrate isbetween an orthographic projection of dam glue on the base substrate andthe display region, and/or an orthographic projection of at least one ofthe plurality of cover plate alignment marks on the base substrate isbetween the orthographic projection of the dam glue on the basesubstrate and the cutting region.

For example, the at least one of the plurality of cover plate alignmentmarks, of which the orthographic projection on the base substrate isbetween the orthographic projection of the dam glue on the basesubstrate and the cutting region, is not overlapped with the secondinorganic encapsulation layer in the direction perpendicular to the basesubstrate.

For example, the at least one of the plurality of cover plate alignmentmarks, of which the orthographic projection on the base substrate isbetween the orthographic projection of the dam glue on the basesubstrate and the cutting region, is at least partially overlapped withthe second inorganic encapsulation layer in the direction perpendicularto the base substrate.

For example, the display substrate comprises a touch structure, thetouch structure is between the encapsulation layer and the opticaladhesive layer in the direction perpendicular to the base substrate, andthe touch structure comprises at least one metal layer, and the at leastone metal layer comprises the plurality of cover plate alignment marks.

For example, a maximum size of an orthographic projection of each of theplurality of cover plate alignment marks on the base substrate rangesfrom 150 microns to 600 microns.

For example, an orthographic projection of each of the plurality ofcover plate alignment marks on the base substrate comprises at least oneshape selected from a group consisting of a T shape, a cross shape, andan L shape.

For example, a surface of the display substrate directly bearing theplurality of cover plate alignment marks is a flat surface.

For example, the frame region comprises a first frame region and asecond frame region which are opposite to each other in a firstdirection; the display panel further comprises a flexible circuit board,and the flexible circuit board is connected with the second frameregion; and the first frame region is provided with the at least one ofthe plurality of cover plate alignment marks located between the damglue and the display region and overlapping with the second inorganicencapsulation layer in the direction perpendicular to the basesubstrate, and/or the second frame region is provided with the at leastone of the plurality of cover plate alignment marks located between thedam glue and the cutting region.

For example, the frame region further comprises a third frame region anda fourth frame region which are opposite to each other in a seconddirection different from the first direction, and the display panelcomprises a curved portion in at least one of the third frame region andthe fourth frame region, and a portion of the cover plate correspondingto the curved portion is curved; the display panel further comprises agate electrode driver in at least one of the third frame region and thefourth frame region; and the plurality of cover plate alignment marksare located outside the third frame region and the fourth frame region.

For example, the plurality of cover plate alignment marks comprise fourcover plate alignment marks, the four cover plate alignment marks arerespectively numbered as a first cover plate alignment mark, a secondcover plate alignment mark, a third cover plate alignment mark, and afourth cover plate alignment mark in an anticlockwise direction; withrespect to an axis parallel to the first direction, a combination of thefirst cover plate alignment mark and the second cover plate alignmentmark is symmetrical with a combination of the third cover platealignment mark and the fourth cover plate alignment mark.

For example, the display substrate further comprises an electrode layerextending portion electrically connected with the plurality of lightemitting elements, and the electrode layer extending portion is in theframe region; in the direction perpendicular to the base substrate, theelectrode layer extending portion is between the plurality of coverplate alignment marks and the base substrate; and an orthographicprojection of the electrode layer extending portion on the basesubstrate is overlapped with orthographic projections of the pluralityof cover plate alignment marks on the base substrate.

For example, the electrode layer extending portion comprises a firstconductive layer and a second conductive layer which are stacked, thesecond conductive layer is on a side of the first conductive layer awayfrom the base substrate, and the second conductive layer comprises aportion recessed toward the base substrate, the portion is electricallyconnected with the first conductive layer, and the plurality of coverplate alignment marks are in a recessed region defined by the portion.

For example, the second conductive layer comprises a firstsub-conductive layer, a second sub-conductive layer, and a thirdsub-conductive layer which are sequentially arranged on the basesubstrate and connected in parallel; and the first sub-conductive layeris between the second sub-conductive layer and the base substrate in thedirection perpendicular to the base substrate.

For example, the display panel further comprises at least one switchingelement, each of the at least one switching element comprises a gateelectrode, a source electrode, and a drain electrode; each of theplurality of light emitting elements comprises a first electrode layerand a second electrode layer, the first sub-conductive layer is in asame layer and made of a same material as the source electrode and drainelectrode, the second sub-conductive layer is in a same layer and madeof a same material as the first electrode layer, and the thirdsub-conductive layer is in a same layer and made of a same material asthe second electrode layer.

For example, the second frame region is provided with a circuit boardalignment mark configured for bending the flexible circuit board, and anorthographic projection of the circuit board alignment mark on the basesubstrate is spaced apart from the orthographic projections of theplurality of cover plate alignment marks on the base substrate; and theorthographic projection of the circuit board alignment mark on the basesubstrate has a maximum size, an orthographic projection of each of theplurality of cover plate alignment marks on the base substrate has amaximum size, and the maximum size of the circuit board alignment markis smaller than the maximum size of each of the plurality of cover platealignment marks.

For example, the cover plate comprises a window region in the displayregion and a light shielding portion located outside the display region;the orthographic projections of the plurality of cover plate alignmentmarks on the base substrate are in a region where an orthographicprojection of the light shielding portion on the base substrate islocated.

For example, each of the plurality of cover plate alignment marks has anintegrated structure.

For example, a material of the plurality of cover plate alignment markscomprises a metal.

For example, the plurality of cover plate alignment marks are opaque.

Embodiments of the present disclosure further provide a manufacturingmethod of a display panel, which comprises: forming a pixel defininglayer on a flexible base substrate; forming a plurality of lightemitting elements on the base substrate, in which the pixel defininglayer separates the plurality of light emitting elements; forming anencapsulation layer on the base substrate, in which the encapsulationlayer is on a side of the plurality of light emitting elements away fromthe base substrate, and the encapsulation layer comprises a firstinorganic encapsulation layer, a first organic encapsulation layer, anda second inorganic encapsulation layer which are sequentially arrangedin a direction away from the base substrate; forming a plurality ofcover plate alignment marks on the base substrate, in which the coverplate alignment marks are configured for aligning a display substratecomprising the pixel defining layer, the plurality of light emittingelements, the encapsulation layer, and the plurality of cover platealignment marks with a cover plate; the display panel comprises adisplay region and a frame region at a periphery of the display region;the frame region comprises a dam glue region where an annular dam glueis located and an annular cutting region on a side of the dam glue awayfrom the display region; at least one of the plurality of cover platealignment marks is overlapped with the second inorganic encapsulationlayer in a direction perpendicular to the base substrate, and anorthographic projection of the at least one of the plurality of coverplate alignment marks on the base substrate is between an orthographicprojection of the dam glue on the base substrate and the display region,and/or an orthographic projection of at least one of the plurality ofcover plate alignment marks on the base substrate is between theorthographic projection of the dam glue and the cutting region; formingan optical adhesive layer on a side of the plurality of cover platealignment marks away from the base substrate; and connecting the displaysubstrate formed with the plurality of cover plate alignment marks tothe cover plate by using the optical adhesive layer, wherein the basesubstrate comprised in the display substrate is flat before connectingthe display substrate to the cover plate and comprises a curved portionafter connecting the display substrate to the cover plate.

For example, the cover plate comprises a window portion in the displayregion and a light shielding portion located outside the display region,and orthographic projections of the plurality of cover plate alignmentmarks on the base substrate is in a region where an orthographicprojection of the light shielding portion on the base substrate islocated.

For example, connecting the display substrate formed with the pluralityof cover plate alignment marks to the cover plate by using the opticaladhesive layer comprises: irradiating the cover plate and the displaysubstrate by light to align the display substrate with the cover plate.

For example, in a case wherein the cover plate and the display substrateare irradiated by light, a center of the display region of the displaysubstrate is calculated according to the plurality of cover platealignment marks by using an alignment device, and a center of the windowportion of the cover plate is calculated according to an edge of thewindow portion of the cover plate by using the alignment device; and thecenter of the display region of the display substrate is aligned withthe center of the window portion of the cover plate by using thealignment device to align the display substrate with the cover plate.

Embodiments of the present disclosure further provide an alignmentmethod, which comprises: irradiating a display substrate and a coverplate for forming a display panel by light, in which the display panelhas a display region and a frame region at a periphery of the displayregion; the display panel comprises the display substrate, the coverplate and an optical adhesive layer connecting the display substrate tothe cover plate, the display substrate comprises a plurality of coverplate alignment marks, and the cover plate comprises a window portion inthe display region and a light shielding portion in the frame region;calculating a center of the display region of the display substrateaccording to the plurality of cover plate alignment marks; calculating acenter of a window portion of the cover plate according to an edge ofthe window portion of the cover plate; and aligning the center of thedisplay region of the display substrate with the center of the windowportion of the cover plate to align the display substrate with the coverplate, in which the display substrate comprises a flexible basesubstrate and comprises a plurality of light emitting elements, a pixeldefining layer, and an encapsulation layer, the plurality of lightemitting elements, the pixel defining layer, and the encapsulation layerare on the base substrate, the pixel defining layer separates theplurality of light emitting elements, and the encapsulation layer is ona side of the plurality of light emitting elements away from the basesubstrate; the optical adhesive layer is on a side of the encapsulationlayer away from the base substrate; the cover plate is on a side of theoptical adhesive layer away from the display substrate; theencapsulation layer comprises a first inorganic encapsulation layer, afirst organic encapsulation layer, and a second inorganic encapsulationlayer which are sequentially arranged in a direction away from the basesubstrate; the frame region comprises a dam glue region where an annulardam glue is located and an annular cutting region which is on a side ofthe dam glue away from the display region; at least one of the pluralityof cover plate alignment marks is overlapped with the second inorganicencapsulation layer in a direction perpendicular to the base substrate,and an orthographic projection of the at least one of the plurality ofcover plate alignment marks on the base substrate is between anorthographic projection of the dam glue on the base substrate and thedisplay region, and/or an orthographic projection of at least one of theplurality of cover plate alignment marks on the base substrate isbetween the orthographic projection of the dam glue and the cuttingregion.

Embodiments of the present disclosure further provide a display panel,which comprises a display substrate, an optical adhesive layer, and acover plate. The display substrate comprises a flexible base substrateand comprises a plurality of light emitting elements, a pixel defininglayer, and an encapsulation layer, in which the plurality of lightemitting elements, the pixel defining layer, and the encapsulation layerare on the base substrate, the pixel defining layer separates theplurality of light emitting elements, and the encapsulation layer is ona side of the plurality of light emitting elements away from the basesubstrate; the optical adhesive layer is on a side of the encapsulationlayer away from the base substrate; and the cover plate is on a side ofthe optical adhesive layer away from the display substrate and connectedwith the display substrate through the optical adhesive layer, in whichthe encapsulation layer comprises a first inorganic encapsulation layer,a first organic encapsulation layer, and a second inorganicencapsulation layer which are sequentially arranged in a direction awayfrom the base substrate; and the display substrate further comprises aplurality of cover plate alignment marks configured for aligning thedisplay substrate with the cover plate, and further comprises a touchstructure, the touch structure is between the encapsulation layer andthe optical adhesive layer in a direction perpendicular to the basesubstrate, and the touch structure comprises at least one metal layer,the at least one metal layer comprises the plurality of cover platealignment marks.

For example, the display panel comprises a display region and a frameregion at a periphery of the display region, the frame region comprisesa dam glue region where an annular dam glue is located and an annularcutting region on a side of the dam glue away from the display region;at least one of the plurality of cover plate alignment marks isoverlapped with the second inorganic encapsulation layer in thedirection perpendicular to the base substrate, and an orthographicprojection of the at least one of the plurality of cover plate alignmentmarks on the base substrate is between an orthographic projection of thedam glue on the base substrate and the display region, and/or anorthographic projection of at least one of the plurality of cover platealignment marks on the base substrate is between the orthographicprojection of the dam glue on the base substrate and the cutting region.

In the embodiments of the present disclosure, each of the plurality ofcover plate alignment marks 14 can have a larger size without increasingthe size of the frame region. In this way, the alignment between thedisplay substrate 10 and the cover plate 30 included in the displaypanel is facilitated, so that the alignment accuracy can be improved,the phenomenon that an edge of the display region is blurred in adisplay panel, especially in a curved display panel (for example, adisplay panel with curved edge regions) can be avoided, and theproduction efficiency can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to clearly illustrate the technical solution of the embodimentsof the present disclosure, the drawings of the embodiments will bebriefly described in the following; it is obvious that the describeddrawings are only related to some embodiments of the present disclosureand thus are not limitative of the present disclosure.

FIG. 1A is a schematic plan view of a display panel provided by anembodiment of the present disclosure;

FIG. 1B is a schematic diagram of a positional relationship of somestructures in a display region of a display panel provided by anembodiment of the present disclosure;

FIG. 1C is a schematic diagram showing the difference between the upperand lower film layers at a cover plate alignment mark and film layers atother positions in a first frame of a display panel provided by anembodiment of the present disclosure;

FIG. 1D is a partial cross-sectional view of a part of structures in afirst frame region of the display panel provided by an embodiment of thepresent disclosure at a line I-I in FIG. 1A;

FIG. 1E is a first partial cross-sectional schematic diagram of a partof structures in a second frame region of the display panel provided byan embodiment of the present disclosure at a line II-II in FIG. 1A;

FIG. 1F is a second partial cross-sectional schematic diagram of a partof structures in a second frame region of the display panel provided byan embodiment of the present disclosure at a line II-II in FIG. 1A;

FIG. 1G is a partial schematic plan view of a light emitting element anda pixel defining layer in a display panel provided by an embodiment ofthe present disclosure;

FIG. 1H is a schematic diagram showing a positional relationship of asecond electrode layer, a cover plate alignment mark, a display region,a recessed region, and a dam glue region in a display panel provided byan embodiment of the present disclosure;

FIG. 2A is a schematic plan view of a dam glue including a first damglue and a second dam glue in a display panel provided by an embodimentof the present disclosure;

FIG. 2B is a partial cross-sectional schematic diagram of a part ofstructures in a first frame region of the display panel provided by anembodiment of the present disclosure along a line in FIG. 2A;

FIG. 3A is a partial cross-sectional schematic diagram along a firstdirection x in FIG. 1A;

FIG. 3B is a partial sectional schematic diagram along a seconddirection y in FIG. 1A;

FIG. 4 is a schematic plan view of a cover plate in a display panelprovided by an embodiment of the present disclosure;

FIGS. 5A and 5B are schematic plan views of touch electrodes and touchsignal lines in a display panel provided by an embodiment of the presentdisclosure; and

FIG. 6 is a schematic diagram of an alignment device, a displaysubstrate, and a cover plate in an embodiment of the present disclosure.

DETAILED DESCRIPTION

In order to make objects, technical details and advantages of theembodiments of the present disclosure apparent, the technical solutionsof the embodiment will be described in a clearly and fullyunderstandable way in connection with the drawings related to theembodiments of the present disclosure. It is obvious that the describedembodiments are just a part but not all of the embodiments of thepresent disclosure. Based on the described embodiments herein, thoseskilled in the art can obtain other embodiment(s), without any inventivework, which should be within the scope of the present disclosure.

Unless otherwise defined, all the technical and scientific terms usedherein have the same meanings as commonly understood by one of ordinaryskill in the art to which the present disclosure belongs. The terms“first,” “second,” etc., which are used in the description and theclaims of the present application for disclosure, are not intended toindicate any sequence, amount or importance, but distinguish variouscomponents. The terms “comprise,” “comprising,” “include,” “including,”etc., are intended to specify that the elements or the objects statedbefore these terms encompass the elements or the objects and equivalentsthereof listed after these terms, but do not preclude the other elementsor objects. The phrases “connect”, “connected”, etc., are not intendedto define a physical connection or mechanical connection, but mayinclude an electrical connection, directly or indirectly. “Upper”,“lower”, “left” and “right” are only used to express the relativepositional relationship. When the absolute position of the describedobject changes, the relative positional relationship may also changeaccordingly.

At present, based on the advantages of flexible display of OLED displaydevices, more and more OLED display devices are designed with two curvedlateral edge regions to improve the visual experience of users. Theinventor(s) of the present application noticed in a research that theOLED display devices with two curved lateral edge regions are prone to aphenomenon that an edge of the display region is blurred, and found thatthis phenomenon is caused by low alignment accuracy between an OLEDdisplay substrate and a cover plate included in the OLED displaydevices.

Based on the above findings, the inventor(s) of the present applicationprovides a display panel and a manufacturing method thereof.

As illustrated by FIGS. 1A to 2B, the display panel includes a displaysubstrate 10, an optical adhesive layer 20, and a cover plate 30. Thecover plate 30 is located on a side of the optical adhesive layer 20away from the display substrate 10, and is connected to the displaysubstrate 10 through the optical adhesive layer 20.

The display substrate 10 includes a flexible base substrate 11 (notlabeled in FIG. 1A), and includes a plurality of light emitting elements12 (as illustrated by FIG. 1G), a pixel defining layer PDL, and anencapsulation layer EPL, the plurality of light emitting elements 12,the pixel defining layer PDL, and the encapsulation layer EPL aredisposed on the base substrate 11. The pixel defining layer PDL is usedto separate the plurality of light emitting elements 12 (as illustratedby FIG. 1G), that is, the pixel defining layer PDL is used to define aplurality of sub-pixel regions, each of which is provided with one lightemitting element 12.

The display substrate 10 further includes an encapsulation layer EPL,which is located on a side of the plurality of light emitting elements12 away from the base substrate 11, for preventing water, oxygen and thelike in the air from corroding the plurality of light emitting elements12. In some embodiments, the encapsulation layer EPL includes a firstinorganic encapsulation layer EPL1, a first organic encapsulation layerEPL3, and a second inorganic encapsulation layer EPL2 (as illustrated byFIG. 1B) arranged in sequence in a direction away from the basesubstrate 11, that is, distances from the first inorganic encapsulationlayer EPL1, the first organic encapsulation layer EPL3, and the secondinorganic encapsulation layer EPL2 to the base substrate 11 graduallyincrease.

The display panel includes a display region (i.e., a region surroundedby the dashed line A in FIG. 1A, FIG. 2A and FIG. 1H) and a frame regionat a periphery of the display region, the frame region includes a damglue region where an annular dam glue 50 is located (i.e., a regionbetween the dashed line D and the dashed line E in FIG. 1H) and anannular cutting region outside the dam glue 50 (i.e., the cutting regionis located on a side of the dam glue 50 away from the display region,i.e., an orthographic projection of the dam glue 50 on the basesubstrate 11 is located between the display region and the cuttingregion).

The display substrate 10 further includes a plurality of cover platealignment marks 14 configured for aligning the display substrate 10 withthe cover plate 30. The plurality of cover plate alignment marks 14 arelocated in the frame region. By arranging the plurality of cover platealignment marks 14 in the frame region, it is able to prevent theplurality of cover plate alignment marks 14 from affecting the displayeffect. In some embodiments, an orthographic projection of at least oneof the plurality of cover plate alignment marks 14 on the base substrateis located between the orthographic projection of the dam glue 50 on thebase substrate and the display region, that is, between the dam glueregion and the display region (as illustrated by FIG. 1A) and the atleast one of the plurality of cover plate alignment marks 14 isoverlapped with the second inorganic encapsulation layer EPL2 in adirection perpendicular to the base substrate 11 (as illustrated byFIGS. 1C, 1D, 1F, and 2B), and an orthographic projection of at leastanother one of the plurality of cover plate alignment marks 14 on thebase substrate is located between the orthographic projection of the damglue 50 on the base substrate and the cutting region (as illustrated byFIG. 1A), i.e., is located between the dam glue region and the cuttingregion.

In some embodiments, with regard to each of the at least one of theplurality of cover plate alignment marks 14 located between the dam glueregion and the cutting region, the second inorganic encapsulation layerEPL2 covers all or only a part of the at least one of the plurality ofcover alignment marks 14 located between the dam glue region and thedisplay region. Or, as illustrated in FIG. 1C and FIG. 1D, in adirection perpendicular to the base substrate 11, the second inorganicencapsulation layer EPL2 is located between the base substrate 11 andthe at least one of the plurality of cover plate alignment marks 14located between the dam glue region and the display region. That is tosay, in some embodiments, with regard to the at least one of theplurality of cover plate alignment marks 14, its orthographic projectionon the base substrate is located between the orthographic projection ofthe dam glue 50 on the base substrate and the display region (asillustrated by FIG. 1A) and the at least one of the plurality of coverplate alignment marks 14 is overlapped with the second inorganicencapsulation layer EPL2 in the direction perpendicular to the basesubstrate 11 (“overlapped” includes “completely overlapped” and“partially overlapped”, and also includes “covering” and “beingcovered”).

In some embodiments, with regard to each of the at least one of theplurality of cover alignment marks 14 of which orthographic projectionon the base substrate is located between the orthographic projection ofthe dam glue 50 on the base substrate and the cutting region, the coveralignment mark 14 is overlapped with (as illustrated by FIG. 1F and FIG.2B) or not overlapped (as illustrated by FIG. 1E) with the secondinorganic encapsulation layer EPL2 in the direction perpendicular to thebase substrate 11. In some embodiments, with regard to each of the atleast one of the plurality of cover alignment marks 14 of whichorthographic projection on the base substrate is located between the damglue region and the cutting region, the second inorganic encapsulationlayer EPL2 covers all or only a part of the at least one of theplurality of cover plate alignment mark 14 located between the dam glueregion and the cutting region. That is to say, in some embodiments, withregard to the at least one of the plurality of cover plate alignmentmarks 14, the orthographic projection of the at least one of theplurality of cover plate alignment marks 14 on the base substrate islocated between the orthographic projection of the dam glue 50 on thebase substrate and cutting region (as illustrated by FIG. 1A) and the atleast one of the plurality of cover plate alignment marks 14 isoverlapped with or not overlapped with the second inorganicencapsulation layer EPL2 in the direction perpendicular to the basesubstrate 11 (“overlapped” includes “completely overlapped” and“partially overlapped”, and also includes “covering” and “beingcovered”). That is to say, in some embodiments, the orthographicprojection of the at least one of the plurality of cover plate alignmentmarks 14 on the base substrate is located between the orthographicprojection of the dam glue 50 on the base substrate and the cuttingregion, that is, is located between the dam glue region and the cuttingregion.

In some embodiments, the dam glue 50 is used to prevent the organicmaterial used to form the organic encapsulation layer in theencapsulation layer EPL from flowing to the outside of the dam glue 50in the process of manufacturing the encapsulation layer EPL, and theoutside of the dam glue 50 is a region between the dam glue 50 and anedge 11A (as illustrated in FIG. 1A) of the base substrate 11. Becausethe dam glue 50 is convex, in order to prevent the shape and size of thecover plate alignment mark 14 from being affected by the dam glue 50,the orthographic projection of the cover plate alignment mark 14 on thebase substrate 11 is located outside a region where the orthographicprojection of the dam glue 50 on the base substrate 11 is located, thatis, the cover plate alignment mark 14 is located outside the dam glueregion.

In some embodiments, the cutting region is a region close to an edge ofthe display panel. Because the display panel is obtained by cutting amother board of the display panel, there is a region close to the edgeof the display panel where a surface of the base substrate 11 is roughdue to cutting, and this region is called as the cutting region. Becausethe surface of the cutting region is rough, in order to prevent thecutting region from affecting the shape and size of the cover platealignment mark 14, orthographic projections of the plurality of coverplate alignment marks 14 on the base substrate 11 are located outsidethe cutting region. In some embodiments, the cutting region includes acrack blocking member for preventing a crack from spreading to thedisplay region during cutting.

In the embodiments of the present disclosure, because the orthographicprojection of at least one of the plurality of cover plate alignmentmarks 14 included in the display substrate 10 is located between theorthographic projection of the dam glue 50 and the display region and/orthe orthographic projection of at least one of the plurality of coverplate alignment marks 14 is located between the orthographic projectionof the dam glue 50 and the cutting region, each of the plurality ofcover plate alignment marks 14 can have a larger size without increasingthe size of the frame region. In this way, the alignment between thedisplay substrate 10 and the cover plate 30 included in the displaypanel is facilitated, so that the alignment accuracy can be improved,the phenomenon that an edge of the display region is blurred in adisplay panel, especially in a curved display panel (for example, adisplay panel with curved edge regions) can be avoided, and theproduction efficiency can be improved.

It should be noted that, in the embodiments of the present disclosure, acomponent A is located on a side of a component B away from the basesubstrate, which refers to that the component B is located between thecomponent A and the base substrate in the direction perpendicular to thebase substrate. A component C is overlapped with a component D or thecomponent C is overlapped with the component D in the directionperpendicular to base substrate 11, which refers to that an orthographicprojection of the component C on base substrate 11 is at least partiallyoverlapped with an orthographic projection of the component D on basesubstrate 11.

For example, as illustrated in FIG. 1A, the plurality of cover platealignment marks 14 included in the display substrate 10 include fourcover plate alignment marks 141 to 144, in which orthographicprojections of two cover plate alignment marks 141 and 144 on the basesubstrate are located between the orthographic projection of the damglue 50 on the base substrate and the display region, and orthographicprojections of the other two cover plate alignment marks 142 and 143 onthe base substrate are located between the orthographic projection ofthe dam glue 50 on the base substrate and the cutting region. It shouldbe noted that, in the embodiment shown in FIG. 1A, the case where thedisplay substrate 10 includes four cover plate alignment marks 14 istaken as an example to illustrate. In other embodiments, the displaysubstrate 10 may include other numbers of cover plate alignment marks14.

The encapsulation layer EPL includes at least two inorganicencapsulation layers and at least one organic encapsulation layer. Inthe case where the encapsulation layer EPL includes at least twoinorganic encapsulation layers and at least two organic encapsulationlayers, the inorganic encapsulation layers and the organic encapsulationlayers are alternately arranged. For example, the first inorganicencapsulation layer EPL1 and the second inorganic encapsulation layerEPL2 are the outermost inorganic encapsulation layers of theencapsulation layer EPL. For example, as illustrated in FIG. 1B, theencapsulation layer EPL only includes a first inorganic encapsulationlayer EPL1 and a second inorganic encapsulation layer EPL2 which arestacked and a first organic encapsulation layer EPL3 located between thefirst inorganic encapsulation layer EPL1 and the second inorganicencapsulation layer EPL2, and the first organic encapsulation layer EPL3directly contacts the first inorganic encapsulation layer EPL1 and thesecond inorganic encapsulation layer EPL2. For example, theencapsulation layer EPL includes a second organic encapsulation layerand a third inorganic encapsulation layer in addition to the firstinorganic encapsulation layer EPL1, the first organic encapsulationlayer EPL2, and the second inorganic encapsulation layer EPL2 which aresequentially stacked, so that the encapsulation layer EPL includes thefirst inorganic encapsulation layer EPL1, the second organicencapsulation layer, the third inorganic encapsulation layer, the firstorganic encapsulation layer EPL2, and the second inorganic encapsulationlayer EPL2 which are sequentially stacked. Or, the encapsulation layerEPL includes a first inorganic encapsulation layer EPL1, a first organicencapsulation layer EPL3, a third inorganic encapsulation layer, asecond organic encapsulation layer and a second inorganic encapsulationlayer EPL2 which are sequentially stacked. In other embodiments, theencapsulation layer EPL may also include more inorganic encapsulationlayers and more organic encapsulation layers.

It should be noted that, in at least one embodiment, at least oneinorganic encapsulation layer included in the encapsulation layer EPLmay extend to a region where the dam glue 50 is located (that is, the atleast one inorganic encapsulation layer may be at least partiallyoverlapped with the dam glue 50 in the direction perpendicular to thebase substrate 11). For example, as illustrated in FIG. 2B, the firstinorganic encapsulation layer EPL1 and the second inorganicencapsulation layer EPL2 included in the encapsulation layer EPL areoverlapped with the dam glue 50. In other embodiments, only the secondinorganic encapsulation layer EPL2 is at least partially overlapped withthe dam glue 50. Or, the whole encapsulation layer EPL is not overlappedwith the dam glue 50 (that is, the whole orthographic projection of theencapsulation layer EPL on the base substrate 11 is located outside theorthographic projection of the dam glue 50 on the base substrate 11).

For example, as illustrated in FIG. 2A and FIG. 2B, the dam glue regionwhere the dam glue 50 is located is provided with a first dam glue 51and a second dam glue 52 arranged in a direction parallel to the basesubstrate 11 (i.e., the dam glue 50 includes a first dam glue 51 and asecond dam glue 52), the second dam glue 52 is farther away from thedisplay region than the first dam glue 51, and a height of the seconddam glue 52 (i.e., a largest distance from the top of the second damglue 52 to the base substrate 11) is larger than a height of the firstdam glue 51 (a largest distance from the top of the first dam glue 51 tothe base substrate 11). For example, the first dam glue 51 includesportions of the following layers extending into the frame region: thesecond planarization insulating layer PLN2, the pixel defining layerPDL, the first inorganic encapsulation layer EPL1, the second inorganicencapsulation layer EPL2, the buffer layer BFL, and the secondintermediate insulating layer IIL2. The second dam glue 52 includesportions of the following layers extending into the frame region: thefirst planarization insulating layer PLN1, the second planarizationinsulating layer PLN2, the pixel defining layer PDL, the first inorganicencapsulation layer EPL1, the second inorganic encapsulation layer EPL2,the buffer layer BFL, and the second intermediate insulating layer IIL2.The dam glue 50 further includes a concave structure between the firstdam glue 51 and the second dam glue 52, and portions between the firstdam glue 51 and the second dam glue 52 belonging to organic film layerssuch as the pixel defining layer PDL, the planarization insulatinglayers PLN1 and PLN2 are removed as much as possible to form an annulargroove region 53, as illustrated in FIG. 2A. That is, the organic filmlayers such as the pixel defining layer PDL, the planarizationinsulating layers PLN1 and PLN2 are disconnected (i.e., discontinuous)at the groove region 53. Furthermore, after the encapsulation of thedisplay panel is completed, the encapsulation layer EPL as formed caneffectively prevent water vapor or oxygen from penetrating into theinside of the light emitting elements of the display panel. Embodimentsof the dam glue 50 include but are not limited to the embodiments shownin FIG. 2A and FIG. 2B.

For example, as illustrated in FIG. 1C, FIG. 1E, and FIG. 1F, the basesubstrate 11 includes a first polyimide layer PH, a first inorganiclayer BR1, a second polyimide layer PI2, and a second inorganic layerBR2 stacked in sequence. The base substrate 11 in FIG. 1B, FIG. 1D andFIG. 2B also adopts the same structure as the base substrate 11 shown inFIG. 1C, FIG. 1E and FIG. 1F. In other embodiments, the base substrate11 may be formed of other materials.

For example, in at least one embodiment of the present disclosure, thelight emitting element 12 included in the display substrate 10 is aself-luminous element such as an OLED or a quantum dot light emittingelement. For example, the light emitting element 12 is a top emissiontype, that is, light emitted from the light emitting element 12 isemitted in a direction away from the base substrate 11 (as shown by anarrow direction in FIG. 1B). For example, as illustrated in FIG. 1B, thelight emitting element 12 includes a first electrode layer 121, a secondelectrode layer 122, and a light emitting layer 123 located between thefirst electrode layer 121 and the second electrode layer 122, one of thefirst electrode layer 121 and the second electrode layer 122 is an anodeand the other one is a cathode. In FIG. 1B, the case where the firstelectrode layer 121 is an anode and the second electrode layer 122 is acathode is described as an example, that is, as illustrated in FIG. 1B,the light emitting element 12 includes an anode 121, a light emittinglayer 123, and a cathode 122. In the direction perpendicular to the basesubstrate 11, the light emitting layer 123 is located between the anode121 and the cathode 122, the anode 121 is located between the lightemitting layer 123 and the base substrate 11, and the cathode 122 islocated on a side of the light emitting layer 123 away from the basesubstrate 11. In other embodiments, positions of the anode 121 and thecathode 122 may be interchanged. To better prevent the light emittingelement 12 from being corroded by water and oxygen in the air, forexample, the cathode 122 of the light emitting element 12 directlycontacts the encapsulation layer EPL. In order to avoid affecting thedisplay effect, for example, both the first electrode layer 121 and thesecond electrode layer 122 are transparent.

For example, as illustrated in FIG. 1B, the display substrate 10 furtherincludes a switching element 19 electrically connected to the lightemitting element 12 to control the operating state of the light emittingelement 12. For example, the switching element 19 is a transistor, whichincludes an active layer 191, a gate electrode 192, a source electrode193, and a drain electrode 194. The gate electrode 192 is insulated fromthe active layer 191 by a gate electrode insulating layer GIL, thesource electrode 193 and drain electrode 194 are insulated from the gateelectrode 192 by an intermediate insulating layer IIL1, and the sourceelectrode 193 and drain electrode 194 extend through through-holes inthe first gate insulating layer GIL1, the second gate electrodeinsulating layers GIL2, and the first intermediate insulating layer IIL1to be electrically connected with the active layer 191.

For example, each of the plurality of sub-pixel regions included in thedisplay substrate 10 includes a light emitting element 12 and aswitching element 19 electrically connected to the light emittingelement 12; as illustrated in FIG. 1B, the switching element 19 iselectrically connected to the first electrode layer 121 of the lightemitting element 12 through the drain electrode 194. In this case, thefirst electrode layers 121 of the plurality of light emitting elements12 in the plurality of sub-pixel regions are disconnected from eachother, that is, the first electrode layers 121 located in differentsub-pixel regions are disconnected from each other. In addition, thesecond electrode layers 122 of the plurality of light emitting elements12 in the plurality of sub-pixel regions are disconnected or directlyconnected with each other. In the case that the second electrode layers122 of the plurality of light emitting elements 12 in the plurality ofsub-pixel regions are directly connected, the plurality of lightemitting elements 12 in the plurality of sub-pixel regions share thesame second electrode layer 122. As illustrated in FIG. 1H, anorthographic projection of an edge F of the shared second electrodelayer 122 on the base substrate is located between the display regionand the dam glue region (i.e., the edge F is located between the dashedline A and the dashed line D), and the second electrode layer 122 iscontinuous and covers the entire display region, which can simplifywiring.

For example, as illustrated in FIG. 1B, the display substrate 10 furtherincludes a first planarization insulating layer PLN1 and a secondplanarization insulating layer PLN2 covering the switching element 19,the second planarization insulating layer PLN2 is located on a side ofthe first planarization insulating layer PLN1 away from the basesubstrate 11, and the second planarization insulating layer PLN2 has asubstantially flat surface, so that the light emitting layer 123 of thelight emitting element 12 is formed on the substantially flat surface.For example, the first electrode layer 121 of the light emitting element12 extends into a through-hole penetrating the second planarizationinsulating layer PLN2 to be electrically connected with a connectionportion 194A, and the connection portion 194A extends into athrough-hole penetrating the first planarization insulating layer PLN1and the passivation insulating layer PVX to be electrically connectedwith the switching element 19, so that the first electrode layer 121 iselectrically connected with the switching element 19 through theconnection portion 194A. In addition, “substantially flat” herein doesnot require 100% flat, but refers to that the surface directly bearingthe cover plate alignment marks 14 is substantially flat, that is, theroughness of the surface meets the allowable error in the thin filmmanufacturing process.

For example, as illustrated in FIG. 1A and FIG. 2A, in the display panelprovided by at least one embodiment of the present disclosure, the frameregion includes a first frame region and a second frame region which areopposite in the first direction x, and a third frame region and a fourthframe region which are opposite in the second direction y. The displaypanel further includes a flexible circuit board 40 connected with thesecond frame region, and the flexible circuit board 40 is electricallyconnected with signal lines in the display region to achieve signaltransmission. For example, as illustrated in FIG. 1H, a lead line 70(the number of the lead line 70 may be one or more; the lead line 70 isnot overlapped with the cover plate alignment marks 142, 143, forexample) is electrically connected with the second electrode layer 122of the light emitting element 12 (not shown in FIG. 1H), so that anelectrical signal is applied to the second electrode layer 122 throughthe lead line 70.

It should be noted that FIG. 1A shows a schematic diagram of theflexible circuit board 40 in an unfolded state; after the product isassembled, a portion of the flexible circuit board 40 located in a bentregion of the circuit board is bent to bend the flexible circuit board40 to a back side of the display panel. In addition, the embodimentshown in FIG. 1A is described only by taking the case where the planarshape of the display panel is a rectangle as an example; in otherembodiments, the planar shape of the display panel can be diamond,circle, and other needed shapes.

For example, in at least one embodiment of the present disclosure, bothtwo lateral edge regions of the display panel are curved. For example,as illustrated in FIG. 3A and FIG. 3B, in the first direction x, thedisplay panel is flat in the first frame region and the second frameregion; in the second direction y, the display panel is curved in thethird frame region and the fourth frame region. In some embodiments, inthe first direction x, the display panel is flat in at least one of thefirst frame region and the second frame region; in the second directiony, the display panel is curved in at least one of the third frame regionand the fourth frame region. That is, the display panel includes acurved portion B in at least one of the third frame region and thefourth frame region, and a portion of the cover plate 30 correspondingto the curved portion B is curved, as illustrated in FIG. 3B. Byadopting the design that the lateral edge region is curved, the visualexperience of the user can be improved upon the user watching thedisplay panel. It should be noted that, the embodiments shown in FIG. 3Aand FIG. 3B are only illustrated by taking the case where the displaypanel is curved in the third frame region and the fourth frame regionand is flat (non-curved) in the whole display region as an example.Embodiments of the present disclosure include but are not limited to theembodiments shown in FIG. 3A and FIG. 3B; For example, the display panelmay be curved only in one of the third frame region and the fourth frameregion.

For example, at least one of the first frame region and the second frameregion is provided with the cover plate alignment mark 14. In theembodiments of the present disclosure, because the second frame regionis located on a side of the display panel where the flexible circuitboard 40 is arranged, the second frame region has a larger width (i.e.,the size along the first direction X), so that the signal linesextending from the display region directly enter the second frame regionto be electrically connected with the flexible circuit board 40, and itis convenient for the signal lines led out from the third frame regionand the fourth frame region to be electrically connected with theflexible circuit board 40 at the second frame region. Furthermore, thefirst frame region opposite to the second frame region also has a largerwidth (i.e., the size along the first direction x), so that the signallines extending from the display region first enter the first frameregion, and then enter the second frame region after passing through thethird frame region or the fourth frame region to be electricallyconnected with the flexible circuit board 40. In the embodiments of thepresent disclosure, because the cover plate alignment mark 14 isprovided in at least one of the first frame region and the second frameregion with a larger width, the cover plate alignment mark 14 may have alarger size to improve the identifiability of the cover plate alignmentmark 14, thereby improving the alignment accuracy.

For example, as illustrated in FIG. 1A, the display panel furtherincludes a gate electrode driver 90 for supplying a gate electrodescanning signal to the display region, the gate electrode driver 90 islocated in at least one of the third frame region and the fourth frameregion. Because the gate electrode driver 90 is arranged in the thirdframe region and/or the fourth frame region, and the free space of thethird frame region and/or the fourth frame region is small, the coverplate alignment mark 14 is located outside the third frame region andthe fourth frame region.

In an embodiment of the present disclosure, for example, the alignmentbetween the display substrate and the cover plate can be performed insuch a way that an alignment device acquires a center of the displayregion of the display substrate and a center of the display region ofthe cover plate. For example, as illustrated in FIG. 4 , the cover plate30 includes a transparent window portion 32 located in the displayregion and a light shielding portion 31 (such as ink and other lightshielding materials) located outside the display region to shieldstructures in the frame region, so as to prevent the structures in theframe region from being seen by users, and an inner edge 31A of thelight shielding portion 31 is located at the edge of the display region.The orthographic projections of the plurality of cover plate alignmentmarks 14 on the base substrate 11 are located in a region where anorthographic projection of the light shielding portion 31 on the basesubstrate 11 is located. For example, upon light irradiating the displaypanel, the alignment device can calculate the center of the displayregion of the display substrate 10 according to the plurality of coverplate alignment marks 14 included in the display substrate 10, and thealignment device can calculate the center of the display region of thecover plate 30 according to the edge 31A of the display region. Thealignment device can achieve the alignment between the display substrate10 and the cover plate 30 by aligning the center of the display regionof the display substrate 10 with the center of the display region of thecover plate 30.

For example, in order to simplify the calculation, the orthographicprojections of the plurality of cover plate alignment marks 14 includedin the display substrate 10 on the base substrate 11 have consistentshapes and profiles. In order to further simplify the calculation, theshapes and profiles of the orthographic projections of the plurality ofcover plate alignment marks can be consistent, and the shapes and sizesof the orthographic projections of the plurality of cover platealignment marks are consistent. In other embodiments, the shapes andprofiles of the orthographic projections of the plurality of cover platealignment marks are consistent and at least some of the cover platealignment marks are inconsistent in shapes and sizes.

For example, as illustrated in FIG. 1A, at least one of the plurality ofcover plate alignment marks 14 included in the display substrate 10 islocated in the first frame region and at least another one of theplurality of cover plate alignment marks 14 is located in the secondframe region, that is, both the first frame region and the second frameregion are provided with cover plate alignment marks 14. For example, asillustrated in FIG. 1A, at least one of the plurality of cover platealignment marks 14 is located in the first frame region and theorthographic projection of the at least one of the plurality of coverplate alignment marks 14 is located between the orthographic projectionof dam glue 50 on the base substrate and the display region, while atleast another one of the plurality of cover plate alignment marks 14 islocated in the second frame region and the orthographic projection ofthe at least another one of the plurality of cover plate alignment marks14 is located between the orthographic projection of dam glue 50 on thebase substrate and the cutting region. For example, in otherembodiments, only the first frame region is provided with at least onecover plate alignment mark 14 of which the orthographic projection islocated between the orthographic projection of the dam glue 50 and thedisplay region; or, only the second frame region is provided with atleast one cover plate alignment mark 14 of which the orthographicprojection is located between the orthographic projection of the damglue 50 and the cutting region.

For example, as illustrated in FIG. 1A, the plurality of cover platealignment marks 14 include four cover plate alignment marks 141 to 144,which are distributed in the frame region close to the four corners ofthe display region. The four cover plate alignment marks 14 arerespectively numbered as a first cover plate alignment mark 141, asecond cover plate alignment mark 142, a third cover plate alignmentmark 143, and a fourth cover plate alignment mark 144 in acounterclockwise direction. The first cover plate alignment mark 141 andthe fourth cover plate alignment mark 144 are located in the first frameregion, and the second cover plate alignment mark 142 and the thirdcover plate alignment mark 143 are located in the second frame region.Furthermore, a combination of the first cover plate alignment mark 141and the second cover plate alignment mark 142 is symmetrical with acombination of the third cover plate alignment mark 143 and a fourthcover plate alignment mark 144 with respect to an axis parallel to thefirst direction x (the axis passes through the center of the displayregion of the display substrate 10 and is parallel to the firstdirection x, and is not shown in the figure). The symmetrical design isbeneficial to simplify the calculation of the alignment device.

It should be noted that different cover plate alignment marks located inthe same frame region can be set in the same way. For example, the firstcover plate alignment mark 141 and the fourth cover plate alignment mark144 located in the first frame region can be arranged in the mannershown in the embodiments shown in FIG. 1C, FIG. 1D and FIG. 2B. Thesecond cover plate alignment mark 142 and the third cover platealignment mark 143 located in the second frame region can be arranged inthe manner shown in the embodiments shown in FIG. 1E and FIG. 1F.

For example, in order to further simplify the calculation, the firstcover plate alignment mark 141 and the fourth cover plate alignment mark144 are located in the same horizontal direction (referring to thesecond direction y in FIG. 1A), the second cover plate alignment mark142 and the third cover plate alignment mark 143 are located in the samehorizontal direction, and the first second cover plate alignment mark141 and second cover plate alignment mark 142 are located in the samevertical direction (referring to first direction x in FIG. 1A), and thethird cover plate alignment mark 143 and the fourth cover platealignment mark 144 are located in the same vertical direction.

Because the distance between the dam glue 50 and the display region isrelatively large in the first frame region, for example, in order tomake the cover plate alignment mark 14 have a relatively large sizewithout increasing the size of the frame region, at least one of theplurality of cover plate alignment marks 14 (taking the cover platealignment marks 141 and 144 as an example in FIG. 1A) included in thedisplay substrate 10 is located in the first frame region and betweenthe dam glue 50 and the display region. In this case, for example, asillustrated in FIG. 1C, FIG. 1D, and FIG. 2B, the cover plate alignmentmark 14 (for example, at least one of the cover plate alignment marks141 and 144 in FIG. 1A) located in the first frame region and betweenthe dam glue 50 and the display region is located on a side of theencapsulation layer EPL away from the base substrate 11. For example, asillustrated in FIG. 1C, FIG. 1D, and FIG. 2B, a portion of theencapsulation layer EPL overlapping with the cover plate alignment mark14 does not include the first organic encapsulation layer EPL3.

Because the distance between the dam glue 50 and the cutting region isrelatively large in the second frame region, for example, in order tomake the cover plate alignment mark 14 have a relatively large sizewithout increasing the size of the frame region, at least another one ofthe plurality of cover plate alignment marks 14 (taking the cover platealignment marks 142 and 143 as an example in FIG. 1A) is located in thesecond frame region and between the dam glue 50 and the cutting region.In this case, in at least one embodiment, the whole encapsulation layerEPL2 does not exceed the dam glue 50, and as illustrated in FIG. 1E, thecover plate alignment mark 14 (for example, at least one of the coverplate alignment marks 142 and 143 in FIG. 1A) located in the secondframe region and between the dam glue 50 and the cutting region isoverlapped with the pixel defining layer PDL and is located on a side ofthe pixel defining layer PDL away from the base substrate 11, that is,at least one of the cover plate alignment marks 14 located between thedam glue 50 and the cutting region is not overlapped with the secondinorganic encapsulation layer EPL2 in the direction perpendicular to thebase substrate 11.

In other embodiments, at least one of the plurality of cover platealignment marks 14 located between the dam glue 50 and the cuttingregion is at least partially overlapped with the second inorganicencapsulation layer EPL2 in the direction perpendicular to the basesubstrate 11. For example, in at least another embodiment, the secondinorganic encapsulation layer EPL2 in the encapsulation layer EPLexceeds the dam glue 50, and as illustrated in FIG. 1F, the cover platealignment mark 14 (for example, at least one of the cover platealignment marks 142 and 143 in FIG. 1A) located in the second frameregion and between the dam glue 50 and the cutting region is overlappedwith the second inorganic encapsulation layer EPL2 and is located on aside of the second inorganic encapsulation layer EPL2 away from the basesubstrate 11. Or, in at least another embodiment, the second inorganicencapsulation layer EPL2 in the encapsulation layer EPL exceeds the damglue 50, and the cover alignment mark 14 (for example, at least one ofthe cover alignment marks 142 and 143 in FIG. 1A) located in the secondframe region and between the dam glue 50 and the cutting region isoverlapped with the pixel defining layer PDL and the second inorganicencapsulation layer EPL2 and is located on a side of the secondinorganic encapsulation layer EPL2 away from the base substrate 11.

It should be noted that, in FIG. 1F, a case where the whole cover platealignment mark 14 located in the second frame region and between the damglue region and the cutting region where the dam glue 50 is located isoverlapped with (i.e., completely overlapped) with the second inorganicencapsulation layer EPL2 and is not overlapped with the pixel definitionlayer PDL is described as an example In some embodiments, the wholecover plate alignment mark 14 between the dam glue region and thecutting region may be overlapped with the second inorganic encapsulationlayer EPL2 and overlapped with the pixel defining layer PDL. In someembodiments, a part of the cover alignment mark 14 is overlapped withthe second inorganic encapsulation layer EPL2 and the other part is notoverlapped with the second inorganic encapsulation layer EPL2 (i.e., thecover alignment mark 14 is only partially overlapped with the secondinorganic encapsulation layer EPL2) and is overlapped with or is notoverlapped with the pixel definition layer PDL. In other embodiments, atleast one of the plurality of the cover plate alignment marks 14 ofwhich the orthographic projection on the base substrate 11 is locatedbetween the dam glue region and the cutting region is not overlappedwith the second inorganic encapsulation layer EPL2 in the directionperpendicular to the base substrate 11 and is located on a side of thepixel defining layer PDL away from the base substrate 11 (as illustratedin FIG. 1E). In other embodiments, at least one of the plurality ofcover alignment marks 14 of which the orthographic projection is locatedbetween the dam glue region and the cutting region is not overlappedwith the second inorganic encapsulation layer EPL2 and the pixeldefining layer PDL and is located on a side of a buffer layer BFLincluded in a touch structure 15 (as illustrated in FIG. 1B) away fromthe base substrate 11.

That is to say, with regard to at least one of the plurality of coveralignment marks 14 of which orthographic projection on the basesubstrate 11 is located between the dam glue region and the cuttingregion (as illustrated in FIG. 1A), the at least one of the plurality ofcover alignment marks 14 is not overlapped or at least partiallyoverlapped with the second inorganic encapsulation layer EPL2 in thedirection perpendicular to the base substrate 11 (the at least one ofthe plurality of cover alignment marks 14 is located on a side of thesecond inorganic encapsulation layer EPL2 facing the base substrate 11or on a side of the second inorganic encapsulation layer EPL2 away fromthe base substrate 11); and/or, with regard to the at least one of theplurality of cover plate alignment marks 14 of which orthographicprojection on the base substrate 11 is located between the dam regionand the cutting region (as illustrated in FIG. 1A), the at least one ofthe plurality of cover alignment marks 14 is at least partiallyoverlapped with the pixel defining layer PDL in the directionperpendicular to the base substrate 11 and is located on a side of thepixel defining layer PDL away from the base substrate 11, or is notoverlapped with the pixel defining layer PDL.

For example, the cover plate alignment mark 14 is formed on a flatsurface, that is, the surface of the display substrate 10 directlybearing the cover plate alignment mark 14 is a flat surface. Forexample, as illustrated in FIG. 1C, FIG. 1D and FIG. 2B, in the firstframe region (for example, between the dam glue 50 and the displayregion as illustrated in FIG. 1A), the surface directly bearing thecover plate alignment mark 14 is a part of the surface of the bufferlayer BFL away from the base substrate 11 (i.e., the upper surface), andthis part of the surface of the buffer layer BFL is flat. For example,as illustrated in FIG. 1E and FIG. 1F, in the second frame region (forexample, between the dam glue 50 and the cutting region as illustratedin FIG. 1A), the surface directly bearing the cover plate alignment mark14 is a part of the surface of the buffer layer BFL away from the basesubstrate 11, and this part of the surface of the buffer layer BFL isflat. In the embodiments of the present disclosure, by making thesurface directly bearing the cover plate alignment mark 14 be a flatsurface, it is beneficial to improve the alignment accuracy. It shouldbe noted that “the surface directly bearing the cover plate alignmentmark 14” refers to that the surface is located between the basesubstrate 11 and the cover plate alignment mark 14 in the directionperpendicular to the base substrate 11, and the surface directlycontacts the cover plate alignment mark 14. In addition, “flat” heredoes not require to be 100% flat, but refers to that the surfacedirectly bearing the cover plate alignment mark 14 is substantiallyflat, that is, the roughness of the surface meets the allowable error inthe thin film manufacturing process.

For example, the display panel may also include alignment marks forother purposes in addition to the plurality of cover plate alignmentmarks 14. Among all the alignment marks included in the display panel,for example, the cover plate alignment mark 14 is the alignment markwith the largest size, and the maximum size of the cover plate alignmentmark 14 is much larger than maximum sizes of the alignment marks forother purposes. This is conducive to improving the ability of thealignment device to identify the cover plate alignment marks.

For example, as illustrated in FIG. 1A, the second frame region isprovided with a circuit board alignment mark 41 (in FIG. 1A, two circuitboard alignment marks 41 are taken as an example; in other embodiments,the number of circuit board alignment marks may also be one or more),and the circuit board alignment mark 41 is used for alignment in theprocess of bending the flexible circuit board 40, so that the flexiblecircuit board 40 is bent according to the set bending degree. Forexample, an orthographic projection of the circuit board alignment mark41 on the base substrate 11 is spaced apart from the orthographicprojections of the plurality of cover alignment marks 14 on the basesubstrate 11 (for example, the circuit board alignment mark 41 islocated on a side of the cover plate alignment marks 14 close to theedge 11A of the base substrate 11), and a maximum size of theorthographic projection of the circuit board alignment mark 41 on thebase substrate 11 is smaller than a maximum size of the cover platealignment mark 14 on the base substrate 11. Because the circuit boardalignment mark 41 is spaced apart from the plurality of cover platealignment marks 14 and the size of the circuit board alignment mark 41is smaller than that of the cover plate alignment mark 14, it ispossible to prevent the circuit board alignment mark 41 from affectingthe alignment between the display substrate 10 and the cover plate 30.It should be noted that the maximum size of the orthographic projectionrefers to the maximum size in all directions of the outline of theorthographic projection, that is, the maximum distance between twopoints on the orthographic projection. In addition, the circuit boardalignment mark 41 and the cover plate alignment mark 14 may have thesame shape (i.e., the same outline shape), or may have different shapes.

For example, each of the cover plate alignment marks 14 has anintegrated structure. For example, each circuit board alignment mark 41is also has an integrated structure. A case where both the cover platealignment mark 14 and the circuit board alignment mark 41 have anintegrated structure is taken as an example, as illustrated in FIG. 1A,the orthographic projection of each of the plurality of cover platealignment marks 14 on the base substrate includes a first extendingportion extending along the first direction x and a second extendingportion extending along the second direction y, the first extendingportion and the second extending portion are directly connected, and themaximum size of the second extending portion in the second direction yis the maximum size of the orthographic projection of the cover platealignment mark 14. Similarly, the circuit board alignment mark 41 alsoincludes a first extending portion extending along the first direction xand a second extending portion extending along the second direction y,the first extending portion and the second extending portion aredirectly connected, and the maximum size of the second extending portionin the second direction y is the maximum size of the orthographicprojection of the circuit board alignment mark 41. Furthermore, themaximum size of the second extending portion of the cover alignment mark14 is larger than the maximum size of the second extending portion ofthe circuit board alignment mark 14. It should be noted that eachextending portion of the cover plate alignment mark 14 is a continuousstructure without a closed opening, so that the orthographic projectionof the whole cover plate alignment mark 14 is also a continuousstructure without a closed opening. Similarly, each extending portion ofthe circuit board alignment mark 41 is a continuous structure without aclosed opening, so that the orthographic projection of the whole circuitboard alignment mark 41 is also a continuous structure without a closedopening.

For example, the maximum size of the orthographic projection of thecover plate alignment mark 14 on the base substrate 11 ranges from about150 microns to 600 microns, such as 300 microns to 500 microns. Forexample, each of the plurality of cover plate alignment marks 14 in FIG.1A has a maximum size in the second direction y, and the maximum sizeranges from about 150 microns to 600 microns, such as 300 microns to 500microns, such as about 150 microns, 200 microns, 250 microns, 300microns, 350 microns, 400 microns, 450 microns, 500 microns, or 550microns. By making the cover plate alignment mark 14 have a larger size,it is beneficial for the alignment device to identify the cover platealignment mark 14, thereby improving the alignment accuracy. It shouldbe noted that “about” here refers to being within the allowable errorrange of the manufacturing process. For example, the maximum design sizeof the cover plate alignment mark 14 is d, which ranges from 150 micronsto 600 microns (e.g., 300 microns to 500 microns). However, due to theinfluence of the manufacturing process, the actual maximum size of themanufactured cover plate alignment mark 14 may slightly deviate from themaximum design size, and the difference between the actual maximum sizeand the maximum design size of the cover plate alignment mark 14 in thisembodiment of the present disclosure meets the requirements of theallowable error range. In addition, the allowable error range can be setaccording to actual needs, so it will not be repeated here.

For example, the maximum size of the orthographic projection of thecover plate alignment mark 14 on the base substrate 11 in the firstdirection X is also several hundred microns, such as ranges from about150 microns to 600 microns, such as about 300 microns to 500 microns,and the size of the orthographic projection of the cover plate alignmentmark 14 in the first direction X is smaller than its size in the seconddirection Y, so as to further improve the identifiability of the coverplate alignment mark 14 and further improve the alignment accuracy.

For example, the orthographic projection of the cover plate alignmentmark 14 on the base substrate 11 includes at least one shape selectedfrom a group consisting of a T shape (as illustrated in FIG. 1A), across shape, and an L shape, or the orthographic projection of the coverplate alignment mark 14 is in any other easily recognizable shape. Forexample, the shape of the orthographic projection of the cover platealignment mark 14 on the base substrate 11 is an integrated structure,for example, the T shape, the cross shape and the L shape are allintegrated structures. In other embodiments, the shape of theorthographic projection of the cover plate alignment mark 14 on the basesubstrate 11 may also include a plurality of discrete portions, forexample, the orthographic projection of the alignment mark 14 includes aplurality of spaced concentric circles. Embodiments of the presentdisclosure include, but are not limited to, these enumerate shapes.

For example, in the process of aligning the display substrate 10 withthe cover plate 30, the alignment device can be used for alignment undera light illumination condition. In this case, in order to clearlyidentify the cover plate alignment marks 14, for example, the coverplate alignment marks 14 are opaque. For example, the material of thecover plate alignment mark 14 is an opaque metal, so that the coverplate alignment marks 14 are opaque. In other embodiments, the coverplate alignment mark 14 may also be made of non-metallic opaquematerials.

For example, in the case where the cover plate alignment marks 14 aremade of a metal, an original metal layer of the display substrate can beused to manufacture the cover plate alignment marks 14 to simplify themanufacturing process. For example, in some embodiments, the displaypanel has a touch structure to achieve the touch function, and the touchstructure includes a metal layer, so the cover plate alignment marks 14can be made of the material used to form the metal layer.

Hereinafter, the touch structure included in the display substrate willbe described with reference to FIG. 1B, FIG. 5A and FIG. 5B.

For example, as illustrated in FIG. 1B, the display substrate 10includes a touch structure 15, which is located between theencapsulation layer EPL and the optical adhesive layer 20 in thedirection perpendicular to the base substrate 11. In this case, forexample, the display panel can be manufactured by sequentiallymanufacturing the buffer layer BF, the switching element 19, the firstplanarization insulating layer PLN1, the second planarization insulatinglayer PLN2, the light emitting element 12, and the encapsulation layerEPL on the base substrate 11, then manufacturing the touch structure 15on the base substrate 11 formed with the encapsulation layer EPL, andthen adhering the display substrate 10 formed with the touch structure15 and the cover plate 30 together through the optical adhesive layer20. Compared with the method of manufacturing touch structure on thecover plate and then adhering the cover plate formed with the touchstructure to the display substrate, the embodiments of the presentdisclosure can greatly reduce the costs by forming the touch structure15 in the display substrate 10, and can make the display panel moreintegrated and thinner, and easier to be folded.

For example, the touch structure 15 includes at least one metal layer,and the at least one metal layer includes the cover plate alignmentmarks 14. The manufacturing process can be simplified by locating thecover plate alignment marks 14 in the metal layer included in the touchstructure 15. In addition, because the touch structure 15 is locatedbetween the encapsulation layer EPL and the optical adhesive layer 20,the metal layer included in the touch structure 15 includes the coverplate alignment marks 14, so that it is not needed to increase the sizeof the frame region, which is beneficial to achieve the narrow framedesign. Similarly, in order to further simplify the manufacturingprocess, other alignment marks included in the display substrate 10 (forexample, the circuit board alignment mark 41) can also be manufacturedby using the original metal layer of the display substrate. For example,because other alignment marks (such as the circuit board alignment mark41) included in the display substrate 10 are small in size, thealignment marks can be made of the forming material of the metal layerincluded in the switching element 19 or the light emitting element 12without increasing the space of the frame region. It should be notedthat the orthographic projections of the plurality of cover platealignment marks 14 on the base substrate 11 are spaced apart from theorthographic projections of other alignment marks on the base substrate11, so as to prevent other alignment marks from affecting the alignmentbetween the display substrate 10 and the cover plate 30.

For example, as illustrated in FIG. 1B, the touch structure 15 includestwo conductive layers 15A and 15B separated by the intermediateinsulating layer IIL2, and the conductive layer 15B is located betweenthe conductive layer 15A and the base substrate 11 in a directionperpendicular to the base substrate 11; one of the two conductive layers15A and 15B is an opaque metal layer and the other is a transparentconductive layer or both the conductive layers are opaque metal layers.For example, the conductive layer 15A is a metal layer and includes thecover plate alignment marks 14. Because the conductive layer 15A iscloser to the cover plate 30 than the conductive layer 15B, it isbeneficial to improving the alignment accuracy by locating the coverplate alignment marks 14 in the conductive layer 15A. In otherembodiments, the conductive layer 15B may include the cover platealignment marks 14.

For example, as illustrated in FIG. 5A, a combination of the twoconductive layers 15A and 15B includes a plurality of columns of firsttouch electrodes 151A, a plurality of rows of second touch electrodes151B, and a plurality of touch signal lines 152A, 152 a and 152B, anextending direction of the first touch electrodes 151A and an extendingdirection of the second touch electrodes 151B intersect with each other,and the first touch electrodes 151A and the second touch electrodes 151Bare electrically connected with their corresponding touch signal lines.For example, an end of each of the first touch electrodes 151A close tothe second frame region is electrically connected with a touch signalline 152 a extending directly to the second frame region, an end of eachof the first touch electrodes 151A close to the first frame region iselectrically connected with a touch signal line 152A extending directlyto the first frame region, and the touch signal line 152A enters thesecond frame region after entering the third frame region from the firstframe region. An end of each of the second touch electrodes 151B closeto the fourth frame region is electrically connected with a touch signalline 152B extending directly to the fourth frame region. Because bothends of the first touch electrode 151A are electrically connected withtouch signal lines, the impedance of the first touch electrode can bereduced.

In other embodiments, for example, the touch electrodes and the touchsignal lines included in the touch structure 15 are located in the sameconductive layer and made of the same material (i.e., the touchelectrodes and the touch signal lines are formed by the same conductivefilm). In this case, for example, the same conductive layer is a metallayer.

For example, as illustrated in FIG. 5B, the touch structure 15 includesa plurality of touch electrodes 151 arranged in a matrix and a pluralityof touch signal lines 152, and each of the touch electrodes 151 iselectrically connected with a corresponding touch signal line 152. Forexample, the touch electrodes 151 and the touch signal lines 152 in FIG.5B are located in the same conductive layer.

Because the touch electrodes (referring to the first touch electrodes151A and the second touch electrodes 151B in FIG. 5A and the touchelectrodes 151 in FIG. 5B) are located in the display region, in orderto avoid affecting the display, for example, the touch electrodes aremainly made of transparent conductive materials such as ITO (indium tinoxide) or IZO (indium zinc oxide), or the touch electrodes are made ofmetal materials to be in a grid shape (as illustrated in FIG. 5B, thetouch electrodes 151 have a grid structure). Touch signal lines(referring to the touch signal lines 152A, 152 a and 152B in FIG. 5A)are located in the frame region or touch signal lines (referring totouch signal lines 152 in FIG. 5B) are located in the region betweenadjacent light emitting elements 12 in the display region, which doesnot affect the display, so the touch signal lines are made of metalmaterials, for example, so as to reduce the resistance.

It should be noted that the embodiments shown in FIG. 5A and FIG. 5B areonly used for description, and the arrangement modes of touch electrodesand touch signal lines include but are not limited to the embodimentsshown in FIG. 5A and FIG. 5B.

For example, as illustrated in FIG. 1B, the touch structure 15 furtherincludes a buffer layer BFL. The conductive layer 15B directly covers aside of the buffer layer BFL away from the encapsulation layer EPL, sothat the adhesion of the conductive layer 15B can be improved to preventthe conductive layer 15B from falling off. For example, the buffer layerBFL is a silicon oxynitride layer or other similar inorganic insulatinglayer.

For example, as illustrated in FIG. 1B, the touch structure 15 furtherincludes a protective layer PL located between the conductive layer 15Aand the optical adhesive layer 20 to protect the conductive layer 15A.

For example, as illustrated in FIG. 1C, FIG. 1D and FIG. 2B, the displaysubstrate 10 further includes an electrode layer extending portion 17electrically connected with the light emitting element 12, and theelectrode layer extending portion 17 is located in the frame region. Forexample, the electrode layer extending portion 17 is electricallyconnected with the second electrode layer 122 (e.g., the cathode) of thelight emitting element 12, and is also electrically connected with thelead line 70 (as illustrated in FIG. 1H), so the second electrode layer122 of the light emitting element 12 is electrically connected with thelead line 70 through the electrode layer extending portion 17. In thedirection perpendicular to the base substrate 11, the electrode layerextending portion 17 is located between the cover plate alignment marks14 (referring to FIG. 1C, FIG. 1D and FIG. 2B) and the base substrate11; furthermore, an orthographic projection of the electrode layerextending portion 17 on the base substrate 11 is overlapped with theorthographic projections of the cover plate alignment marks 14 on thebase substrate 11. Because the signal lines in the first frame regionare densely distributed, by arranging the cover plate alignment marks 14in the first frame region on a side of the electrode layer extendingportion 17 away from the base substrate 11, the space of the first frameregion can be effectively utilized without increasing the size of theframe region (that is, it is beneficial to achieve the narrow framedesign).

For example, as illustrated in FIG. 1C and FIG. 2B, the electrode layerextending portion 17 includes a first conductive layer 171 and a secondconductive layer 172 which are stacked, the second conductive layer 172is located on a side of the first conductive layer 171 away from thebase substrate 11, and the second conductive layer 172 has a portionrecessed toward the base substrate 11 with respect to at least part ofthe structures such as the pixel defining layer PDL, the firstplanarization insulating layer PLN1, the second planarization insulatinglayer PLN2 and the like. For example, as illustrated in FIG. 1C, a firstsub-conductive layer 172A, a second sub-conductive layer 172B, and athird sub-conductive layer 172C included in the second conductive layer172 all include portions recessed toward the base substrate 11 withrespect to the second planarization insulating layer PLN2 and the pixeldefining layer PDL. For example, as illustrated in FIG. 2B, a firstsub-conductive layer 172A, a second sub-conductive layer 172B, and athird sub-conductive layer 172C included in the second conductive layer172 all include portions recessed toward the base substrate 11 withrespect to the first planarization insulating layer PLN1, the secondplanarization insulating layer PLN2, and the pixel defining layer PDL.For example, the second conductive layer 172 is electrically connectedto the first conductive layer 171 at the recessed region 170, and thecover plate alignment marks 14 are located in the recessed region 170defined by the second conductive layer 172 (a region between the dashedline B and the dashed line C in FIG. 1H). For example, an orthographicprojection of the recessed region 170 on the base substrate is a closedannular structure between the display region and an orthographicprojection of the edge F of the second electrode layer 122.

For example, as illustrated in FIG. 2B, the first conductive layer 171extends to a side of the second dam glue 52 away from the first dam glue51, the first sub-conductive layer 172A and the second sub-conductivelayer 172B both extend to a region where the second dam glue 52 isarranged in the display substrate 10, and the third sub-conductive layer172C extends to a side of the first dam glue 51 away from the second damglue 52. In this case, for example, the lead line 70 (as illustrated inFIG. 1H) led out from the flexible circuit board 40 is in direct contactwith the first conductive layer 171, so that the lead line 70 iselectrically connected to the second electrode layer 122 of the lightemitting element 12 through the electrode layer extending portion 17. Inother embodiments, the lead line 70 may also directly contact the firstsub-conductive layer 172A and/or the second sub-conductive layer 172B,so that the lead line 70 is electrically connected to the secondelectrode layer 122 of the light emitting element 12 through theelectrode layer extending portion 17.

In an embodiment of the present disclosure, the first planarizationinsulating layer PLN1, the second planarization insulating layer PLN2,and the pixel defining layer PDL extend to the frame region and aredisconnected at the recessed region 170, so that the first conductivelayer 171 and the second conductive layer 172 are overlapped andelectrically connected (e.g., directly contacted) in the recessed region170. The electrode layer extending portion 17 includes the firstconductive layer 171 and the second conductive layer 172 which areconnected in parallel, the resistance of the electrode layer extendingportion 17 can be reduced. By arranging the cover plate alignment marks14 in the recessed region 170, it is able to avoid increasing thethickness of the display substrate in the recessed region 170, which isconducive to achieving the thinning of the display panel. It should benoted that FIG. 2B only shows a partial cross-sectional view of therecessed region 170.

For example, as illustrated in FIG. 1C and FIG. 2B, the secondconductive layer 172 includes a plurality of sub-conductive layersconnected in parallel (for example, portions of the sub-conductivelayers located in the entire recessed region 170 are connected inparallel with each other). For example, the plurality of sub-conductivelayers which are connected in parallel include a first sub-conductivelayer 172A, a second sub-conductive layer 172B, and a thirdsub-conductive layer 172C which are sequentially stacked on the basesubstrate 11. For example, the first sub-conductive layer 172A directlycontacts the second sub-conductive layer 172B in the recessed region 170and the second sub-conductive layer 172B directly contacts the thirdsub-conductive layer 172C in the recessed region 170 to achieve theparallel connection among the three sub-conductive layers. Furthermore,the first sub-conductive layer 172A is located between the secondsub-conductive layer 172B and the base substrate 11 in a directionperpendicular to the base substrate 11. The resistance of the electrodelayer extending portion 17 can be further reduced by making the secondconductive layer 172 include a plurality of sub-conductive layersconnected in parallel.

For example, as illustrated in FIG. 1B, the first source/drain electrodelayer 1710 where the first conductive layer 171 (not shown in FIG. 1B)is located includes the source electrode 193 and the drain electrode 194of the switching element 19, that is, the first source/drain electrodelayer 1710 includes the first conductive layer 171, the source electrode193 and the drain electrode 194. For example, as illustrated in FIG. 1B,the second source/drain electrode layer 1721 where the firstsub-conductive layer 172A (not shown in FIG. 1B) is located includes theconnection portion 194A (i.e., the second source/drain electrode layer1721 includes the first sub-conductive layer 172A and the connectionportion 194A), the connection portion 194A is located between the firstsource/drain electrode layer 1710 and the first electrode in thedirection perpendicular to the base substrate 11, and the connectionportion 194A electrically connects the drain electrode 194 with thefirst electrode layer 121, which is beneficial to a good electricalconnection between the drain electrode 194 and the first electrode layer121 (e.g., the anode) of the light emitting element 12. For example, asillustrated in FIG. 1B, the electrode layer 1722 where the secondsub-conductive layer 172B (not shown in FIG. 1B) is located includes thefirst electrode layer 121 (e.g., the anode) of the light emittingelement 12, that is, the electrode layer 1722 includes the secondsub-conductive layer 172B and the first electrode layer 121. Forexample, as illustrated in FIG. 1B, the electrode layer 1723 where thethird sub-conductive layer 172C (not shown in FIG. 1B) is locatedincludes the second electrode layer 122 (e.g., the cathode) of the lightemitting element 12, that is, the electrode layer 1723 includes thethird sub-conductive layer 172C and the second electrode layer 122, forexample, the third sub-conductive layer 172C is directly connected withthe second electrode layer 122. That is, the first conductive layer 171is disposed in the same layer and made of the same material as thesource electrode 193 and the drain electrode 194, and the firstconductive layer 171 is electrically insulated from the source electrode193/the drain electrode 194. The second sub-conductive layer 172B isdisposed in the same layer and made of the same material as the firstelectrode layer 121 of the light emitting element 12, and iselectrically insulated from the first electrode layer 121. The thirdsub-conductive layer 172C is disposed in the same layer and made of thesame material as the second electrode layer 122 of the light emittingelement 12, and is electrically connected with the second electrodelayer 122 of the light emitting element 12 (for example, the thirdsub-conductive layer 172C is directly connected with the secondelectrode layer 122). In the embodiments of the present disclosure, themanufacturing process of the display panel can be simplified by using aportion of the electrode layers in the display region extending to theframe region to form the electrode layer extending portion 17, which cansimplify the manufacturing process of the display panel.

It should be noted that multiple components being disposed in the samelayer and made of the same material refers to that the multiplecomponents are formed by the same thin film in the same patterningprocess; in addition, the multiple components may be located on the samelayer side by side, or there is a height difference between the multiplecomponents (that is, the distances from the multiple components to thebase substrate 11 are different), or at least one of the multiplecomponents has a convex portion or a recessed portion.

In at least one embodiment of the present disclosure, for example, thewidth of the second frame region is larger than the width of the firstframe region, that is, the size of the second frame region along thefirst direction X is larger than the size of the first frame regionalong the first direction X, which makes the distribution of electrodelayer extending portion 17 in the second frame region sparser than thatin the first frame region, so the cover plate alignment marks 14 in thesecond frame region can be located in a flat region outside the regionwhere the electrode layer extending portion(s) 17 is located. Forexample, as illustrated in FIG. 1E and FIG. 1F, the cover platealignment marks in the second frame region are not overlapped with theelectrode layer extending portion 17.

For example, in the display panel shown in FIG. 1B to FIG. 1F and FIG.2B, the following structures are sequentially provided on the basesubstrate 11: the buffer layer BF, the active layer 191, the first gateelectrode insulating layer GIL1, the gate electrode 192, the second gateelectrode insulating layer GIL2, the first intermediate insulating layerIIL1, the first source/drain electrode layer 1710 including the sourceelectrode 193 and the drain electrode 194 (for example, the firstsource/drain electrode layer 1710 further includes the first conductivelayer 171), the passivation insulating layer PVX, the firstplanarization insulating layer PLN1, the second source/drain electrodelayer 1721 including the connection portion 194A (for example, thesecond source/drain electrode layer 1721 further includes the firstsub-conductive layer 172A), the second planarization insulating layerPLN2, the first electrode layer 121 (for example, the electrode layer1722 where the first electrode layer 121 is located further includes thesecond sub-conductive layer 172B), the pixel defining layer PDL, thelight emitting layer 123, the second electrode layer 122 (for example,the electrode layer 1723 where the second electrode layer 122 is locatedfurther includes the third sub-conductive layer 172C), the encapsulationlayer EPL (which includes, for example, the first inorganicencapsulation layer EPL1, the first organic encapsulation layer EPL3,and the second inorganic encapsulation layer EPL2, in which the firstorganic encapsulation layer EPL3 is not overlapped with the cover platealignment marks 14), and the touch structure 15 (which includes, forexample, the buffer layer BFL, the conductive layer 15B, the secondintermediate insulating layer IIL2, the conductive layer 15A, and theprotective layer PL, the layer where the conductive layer 15B is locatedand/or the layer where the conductive layer 15 is located, for example,includes the plurality of the cover plate alignment marks 14 which arespaced apart). In other embodiments, the display panel may not includesome of the above structures, or may include other structures based onthe above structures, or the positional relationship of the abovestructures in the display panel may change.

At least one embodiment of the present disclosure further provides adisplay panel, as illustrated in FIG. 1A to FIG. 3B, which includes adisplay substrate 10, an optical adhesive layer 20, and a cover plate30. The cover plate is located on a side of the optical adhesive layer20 away from the display substrate 10, and is connected to the displaysubstrate 10 through the optical adhesive layer 20.

As illustrated in FIG. 1B, the display substrate 10 includes a flexiblebase substrate 11 and a plurality of light emitting elements 12 on thebase substrate 11 (only one light emitting element 12 is shown in FIG.1B for illustration), a pixel defining layer PDL, and an encapsulationlayer EPL. The pixel defining layer PDL separates the plurality of lightemitting elements 12, and the encapsulation layer EPL is located on aside of the plurality of light emitting elements 12 away from the basesubstrate 11. An optical adhesive layer 20 is provided on a side of theencapsulation layer EPL away from the base substrate 11. Theencapsulation layer EPL includes a first inorganic encapsulation layerEPL1, a first organic encapsulation layer EPL3, and a second inorganicencapsulation layer EPL2 which are sequentially arranged in thedirection away from the base substrate 11. The display substrate 10further includes a plurality of cover plate alignment marks 14configured for aligning the display substrate 10 with the cover plate30. The display substrate 10 further includes a touch structure 15,which is located between the encapsulation layer EPL and the opticaladhesive layer 20 in a direction perpendicular to the base substrate 11.The touch structure 15 includes at least one metal layer (illustrated bytaking two metal layers 15A and 15B as an example in FIG. 1B), and theat least one metal layer includes the cover plate alignment marks, suchas the cover plate alignment marks 14 in any one of the embodimentsshown in FIG. 1A, FIG. 1C to FIG. 2B. That is, the at least one metallayer included in the touch structure 15 includes a touch electrode anda touch signal line, and at least one of the touch electrode and thetouch signal line is disposed in the same layer and made of the samematerial as the cover plate alignment marks 14, that is, at least one ofthe touch electrode and the touch signal line and the cover platealignment marks 14 are formed by the same thin film. For the descriptionof the touch electrode and the touch signal line, please refer to thedescriptions in the above embodiments, and the repeated portions willnot be described herein.

In the embodiments of the disclosure, because the plurality of coverplate alignment marks 14 included in the display substrate 10 arelocated in at least one metal layer included in the touch structure,each of the plurality of cover plate alignment marks 14 can have arelatively large size without increasing the size of the frame region,which is convenient for the alignment between the display substrate 10and the cover plate 30 included in the display panel, thereby improvingthe alignment accuracy, avoiding the phenomenon that edges of thedisplay region are blurred in a display panel, especially in a curveddisplay panel (for example, a display panel with a curved edge region),and improving the production efficiency.

For example, as illustrated in FIG. 1A, the display panel includes adisplay region and a frame region located at the periphery of thedisplay region, and the frame region includes an annular dam glue 50 andan annular cutting region located outside the dam glue 50. Anorthographic projection of at least one of the plurality of cover platealignment marks 14 included in the display substrate 10 on the basesubstrate 11 is located between an orthographic projection of the damglue 50 on the base substrate 11 and the display region and isoverlapped with the second inorganic encapsulation layer EPL2 in adirection perpendicular to the base substrate 11, and/or an orthographicprojection of at least one of the plurality of cover plate alignmentmarks 14 on the base substrate is located between the orthographicprojection of the dam glue 50 on the base substrate and the cuttingregion.

Embodiments of the present disclosure further provide a manufacturingmethod of the display panel provided by any one of the aboveembodiments. Taking the display panel shown in FIG. 1A to FIG. 3B as anexample, the manufacturing method includes the following steps.

Step S1: forming a pixel defining layer PDL on a flexible base substrate11.

Step S2: forming a plurality of light emitting elements 12 on the basesubstrate 11 (only one light emitting element 12 is shown in FIG. 1B forillustration), and the pixel defining layer PDL separates the pluralityof light emitting elements 12.

Step S3: forming an encapsulation layer EPL on the base substrate 11,and the encapsulation layer EPL is located on a side of the plurality oflight emitting elements 12 away from the base substrate 11, and theencapsulation layer EPL includes a first inorganic encapsulation layerEPL1, a first organic encapsulation layer EPL3, and a second inorganicencapsulation layer EPL2 which are sequentially arranged in a directionaway from the base substrate 11.

Step S4: forming a plurality of cover plate alignment marks 14 on thebase substrate 11, the plurality of cover plate alignment marks 14 areconfigured for aligning the display substrate including the pixeldefining layer PDL, the light emitting elements 12, the encapsulationlayer EPL, and the cover plate alignment marks 14 with the cover plate30; the display panel includes a display region and a frame regionlocated at a periphery of the display region. The frame region includesa dam glue 50 and an annular cutting region located on a side of the damglue 50 away from the display region. An orthographic projection of atleast one of the plurality of cover plate alignment marks 14 on the basesubstrate 11 is located between an orthographic projection of the damglue on the base substrate 11 and display region, and the at least oneof the plurality of cover plate alignment marks 14 is overlapped withthe second inorganic encapsulation layer EPL2 in a directionperpendicular to the base substrate 11, and/or an orthographicprojection of at least one of the plurality of cover plate alignmentmarks 14 on the base substrate 11 is located between the orthographicprojection of the dam glue 50 on the base substrate 11 and cuttingregion.

Step S5: forming an optical adhesive layer 20 on a side of the pluralityof cover plate alignment marks 14 away from the base substrate 11.

Step S6: connecting the display substrate 10 formed with the pluralityof cover plate alignment marks 14 to the cover plate 30 by using theoptical adhesive layer 20, the base substrate 11 of the displaysubstrate 10 is substantially flat before the display substrate 10 isconnected to the cover plate 30 and includes a curved portion B afterthe display substrate 10 is connected to the cover plate 30 (asillustrated in FIG. 3B).

It should be noted that the embodiments of the present disclosure onlyschematically illustrate that the manufacturing method of the displaypanel includes the above steps, and do not limit the manufacturingsequence of the above steps, and the manufacturing sequence of the abovesteps can be adjusted according to actual needs.

For example, as illustrated in FIG. 4 , the cover plate 30 includes awindow portion 32 located in the display region and a light shieldingportion 31 located outside the display region (i.e., the light shieldingportion 31 is located in the frame region), and the orthographicprojections of the plurality of cover plate alignment marks 14 on thebase substrate 11 are located in a region where an orthographicprojection of the light shielding portion 31 on the base substrate 11 islocated. In this case, connecting the display substrate 10 formed withthe plurality of cover plate alignment marks 14 to the cover plate 30 byusing the optical adhesive layer 20 includes: irradiating the coverplate and the display substrate by light, and aligning the displaysubstrate 10 with the cover plate 30 by using the plurality of coverplate alignment marks 14 and the light shielding portion 31, asillustrated in FIG. 6 . For example, in the process of irradiating thecover plate 30 and the display substrate 10 by light, an alignmentdevice 80 can calculate a center of the display region of the displaysubstrate 10 according to the plurality of cover plate alignment marks14 included in the display substrate 10, and the alignment device 80 cancalculate a center of the window portion 32 of the cover plate 30according to an inner edge 31A of the light shielding portion 31 in thecover plate 30 (that is, the edge of the display region). The alignmentdevice 80 can align the display substrate 10 with the cover plate 30 byaligning the center of the display region of the display substrate 10with the center of the window portion 32 of the cover plate 30. Inaddition, during the alignment process, the display substrate 10 and thecover plate 30 are connected together through the optical adhesive layer20.

For example, as illustrated in FIG. 1B, in the case where the displaysubstrate 10 includes a touch structure 15, the manufacturing method ofthe display substrate 10 includes: forming a switch element 19, a firstplanarization insulating layer PLN1, a second planarization insulatinglayer PLN2, a light emitting element 12 (for example, the light emittingelement 12 is formed by an evaporation process), and an encapsulationlayer EPL on the base substrate 11 in sequence, and then forming thetouch structure 15 on a side of the encapsulation layer EPL away fromthe base substrate 11. Compared with the method of manufacturing thetouch structure on the cover plate and then adhering the cover plateformed with the touch structure and the display substrate, theembodiments of the present disclosure can greatly reduce the costs byforming the touch structure 15 in the display substrate 10, and can makethe display panel more integrated and thinner and easier to be folded.

For example, as illustrated in FIG. 1B, forming the touch structure 15includes: forming a conductive layer 15B, an intermediate insulatinglayer IIL2, and a conductive layer 15A sequentially stacked on theencapsulation layer EPL, and a combination of the conductive layer 15Band the conductive layer 15A includes the cover alignment marks 14,touch electrodes (referring to 151A and 151B in FIG. 5A), and touchsignal lines (referring to 152A, 152 a and 152B in FIG. 5A). Themanufacturing process can be simplified by locating the cover platealignment marks 14 in the conductive layer included in the touchstructure 15.

For example, the conductive layer 15A is a metal layer and includes thecover plate alignment marks 14. Because the conductive layer 15A iscloser to the cover plate 30 than the conductive layer 15B, it isbeneficial to improving the alignment accuracy by locating the pluralityof cover plate alignment marks 14 in the conductive layer 15A.

For example, forming the touch structure 15 further includes: formingthe conductive layer 15B directly on the buffer layer BFL on theencapsulation layer EPL, and forming a protective layer PL covering theconductive layer 15A after forming the conductive layer 15A.

In other embodiments, the touch structure 15 includes one conductivelayer, which is a metal layer, and the one conductive layer includes theplurality of cover plate alignment marks 14, a touch electrode(referring to 151 in FIG. 5B), and a touch signal line (referring to 152in FIG. 5B). Embodiments of that present disclosure include, but are notlimited to these enumerate embodiments.

For example, the manufacturing method of the display panel shown in FIG.1A to FIG. 3B includes: sequentially forming the following structures onthe base substrate 11: a switching element 19 (for example, the firstsource/drain electrode layer 1710 where the source electrode 193 and thedrain electrode 194 of the switching element 19 are located alsoincludes the first conductive layer 171), a passivation insulating layerPVX, a first planarization insulating layer PLN1, a second source/drainelectrode layer 174 including a connection portion 194A (for example,the second source/drain electrode layer 1721 also includes a firstsub-conductive layer 172A), a second planarization insulating layerPLN2, a first electrode layer 121 (for example, the electrode layer 1722where first electrode layer 121 is located also includes a secondsub-conductive layer 172B), a pixel defining layer PDL, a light emittinglayer 123, a second electrode layer 122 (for example, the electrodelayer 1723 where the second electrode layer 122 is located also includesa third sub-conductive layer 172C), an encapsulation layer EPL (whichincludes, for example, a first inorganic encapsulation layer EPL1, afirst organic encapsulation layer EPL3, and a second inorganicencapsulation layer EPL2, in which the first organic encapsulation layerEPL3 is not overlapped with the cover plate alignment marks 14), and atouch structure 15 (which includes, for example, a buffer layer BFL, aconductive layer 15B, a second intermediate insulating layer IIL2, aconductive layer 15A, and a protective layer PL, the layer where theconductive layer 15B and/or the conductive layer 15A is located alsoincludes the plurality of cover plate alignment marks 14).

For example, before forming the passivation insulating layer PVX, themanufacturing method of the display panel further comprises:sequentially forming a buffer layer BF, an active layer 191, a firstgate electrode insulating layer GIL1 covering the active layer 191, agate electrode 192 located on a side of the first gate electrodeinsulating layer GIL1 away from the base substrate 11, a second gateelectrode insulating layer GIL2 covering the gate electrode 192, a firstintermediate insulating layer IIL1 covering the second gate electrodeinsulating layer GIL2, and a first source/drain electrode layer 1710located on a side of the first intermediate insulating layer IIL1 awayfrom the base substrate 11. The first source/drain electrode layer 1710includes a source electrode 193 and a drain electrode 194 electricallyconnected to the active layer 191, for example, the source electrode 193and the drain electrode 194 extend through through-holes in the firstintermediate insulating layer IIL1, the second gate electrode insulatinglayer GIL2, and the first gate electrode insulating layer GIL1 to beelectrically connected with the active layer 191.

Upon the structures of the display panel in the embodiments of thepresent disclosure changing, the above steps of the manufacturing methodare adjusted accordingly.

At least one embodiment of the present disclosure further provides analignment method, which can be used for alignment in the manufacturingprocess of the display panel as provided in any one of the embodimentsshown in FIG. 1A to FIG. 3B.

As illustrated in FIG. 1A to FIG. 3B, the display panel which can adoptthe alignment method includes a display substrate 10, an opticaladhesive layer 20, and a cover plate 30. The display panel includes adisplay region and a frame region located at the periphery of thedisplay region. The frame region includes an annular dam glue 50 and anannular cutting region located on a side of the dam glue 50 away fromthe display region. The cover plate 30 is located on a side of theoptical adhesive layer 20 away from the display substrate 10, and isconnected to the display substrate 10 through the optical adhesive layer20. As illustrated in FIG. 4 , the cover plate 30 includes a windowportion 32 located in the display region and a light shielding portion31 located in the frame region. The display substrate 10 includes aflexible base substrate 11 (not labeled in FIG. 1A) and a plurality oflight emitting elements 12 (as illustrated in FIG. 1G), a pixel defininglayer PDL, and an encapsulation layer EPL disposed on the base substrate11. The pixel defining layer PDL is used to separate the plurality oflight emitting elements 12 (as illustrated in FIG. 1G), that is, thepixel defining layer PDL is used to define a plurality of sub-pixelregions, each of the plurality of sub-pixel regions is provided with onelight emitting element 12. The encapsulation layer EPL is located on aside of the plurality of light emitting elements 12 away from the basesubstrate 11, for preventing water, oxygen and the like in the air fromcorroding the plurality of light emitting elements 12. The encapsulationlayer EPL includes a first inorganic encapsulation layer EPL1, a firstorganic encapsulation layer EPL3, and a second inorganic encapsulationlayer EPL2 (as illustrated in FIG. 1B) arranged in sequence in adirection away from the base substrate 11, that is, the distances fromthe first inorganic encapsulation layer EPL1, the first organicencapsulation layer EPL3, and the second inorganic encapsulation layerEPL2 to the base substrate 11 gradually increase. The display substrate10 further includes a plurality of cover plate alignment marks 14configured for aligning the display substrate 10 with the cover plate30. The plurality of cover plate alignment marks 14 are located in theframe region. An orthographic projection of at least one of theplurality of cover plate alignment marks 14 on the base substrate islocated between an orthographic projection of the dam glue 50 on thebase substrate and display region (as illustrated in FIG. 1A) and the atleast one of the plurality of cover plate alignment marks 14 isoverlapped with the second inorganic encapsulation layer EPL2 in thedirection perpendicular to the base substrate 11 (as illustrated in FIG.1C, FIG. 1D, FIG. 2F and FIG. 2B), and an orthographic projection of atleast another one of the plurality of cover plate alignment marks 14 onthe base substrate is located between the orthographic projection of thedam glue 50 on the base substrate and cutting region (as illustrated inFIG. 1A). Or, an orthographic projection of at least one of theplurality of cover plate alignment marks 14 on the base substrate islocated between the orthographic projection of the dam glue 50 on thebase substrate and the display region and the at least one of theplurality of cover plate alignment marks 14 is overlapped with thesecond inorganic encapsulation layer EPL2 in the direction perpendicularto the base substrate 11. Or, an orthographic projection of at least oneof the plurality of cover plate alignment marks 14 on the base substrateis located between the orthographic projection of the dam glue 50 on thebase substrate and the cutting region.

In order to form the display panel as illustrated in FIG. 1A to FIG. 3B,the alignment method includes: irradiating the display substrate 10 andthe cover plate 30 for forming the display panel by light, andcalculating a center of the display region of the display substrate 10according to the plurality of cover plate alignment marks 14 included inthe display substrate 10; calculating a center of the window portion 32of the cover plate 30 according to the edge 31A of the window portion 32(as illustrated in FIG. 4 ); and aligning the center of the displayregion of the display substrate 10 with the center of the window portion32 of the cover plate 30 to align the display substrate 10 with thecover plate 30.

In the embodiments of the present disclosure, because the orthographicprojection of at least one of the plurality of cover plate alignmentmarks 14 included in the display substrate 10 is located between theorthographic projection of the dam glue 50 and the display region and/orthe orthographic projection of at least one of the plurality of coverplate alignment marks 14 is located between the orthographic projectionof the dam glue 50 and the cutting region, each of the plurality ofcover plate alignment marks 14 can have a relatively large size withoutincreasing the size of the frame region. In this way, the alignmentbetween the display substrate 10 and the cover plate 30 included in thedisplay panel is facilitated, so that the alignment accuracy can beimproved, the phenomenon that an edge of the display region is blurredin a display panel, especially in a curved display panel (for example, adisplay panel with curved edge regions) can be avoided, and theproduction efficiency can be improved.

The same components in the above embodiments of the display panel, thealignment method and the manufacturing method of the display panel arearranged in the same way, and the repeated portions are not describedherein.

In case of no conflict, embodiments of the present disclosure andfeatures in embodiments can be combined.

The foregoing is only exemplary embodiments of the present disclosure,and is not intended to limit the protection scope of the presentdisclosure, the protection scope of the present disclosure is determinedby the appended claims.

1. A display panel, comprising: a display substrate, comprising aflexible base substrate and comprising a plurality of light emittingelements, a pixel defining layer, and an encapsulation layer, whereinthe plurality of light emitting elements, the pixel defining layer, andthe encapsulation layer are on the base substrate, the pixel defininglayer separates the plurality of light emitting elements, and theencapsulation layer is on a side of the plurality of light emittingelements away from the base substrate; an optical adhesive layer, on aside of the encapsulation layer away from the base substrate; and acover plate, on a side of the optical adhesive layer away from thedisplay substrate and connected with the display substrate through theoptical adhesive layer, wherein the display panel comprises a displayregion and a frame region at a periphery of the display region; theframe region comprises a dam glue region where an annular dam glue islocated and an annular cutting region which is on a side of the dam glueaway from the display region; the encapsulation layer comprises a firstinorganic encapsulation layer, a first organic encapsulation layer, anda second inorganic encapsulation layer which are sequentially arrangedin a direction away from the base substrate; the display substratefurther comprises a plurality of cover plate alignment marks configuredfor aligning the display substrate with the cover plate; and at leastone of the plurality of cover plate alignment marks is overlapped withthe second inorganic encapsulation layer in a direction perpendicular tothe base substrate, and an orthographic projection of the at least oneof the plurality of cover plate alignment marks on the base substrate isbetween an orthographic projection of dam glue on the base substrate andthe display region, and/or an orthographic projection of at least one ofthe plurality of cover plate alignment marks on the base substrate isbetween the orthographic projection of the dam glue on the basesubstrate and the cutting region.
 2. The display panel according toclaim 1, wherein the at least one of the plurality of cover platealignment marks, of which the orthographic projection on the basesubstrate is between the orthographic projection of the dam glue on thebase substrate and the cutting region, is not overlapped with the secondinorganic encapsulation layer in the direction perpendicular to the basesubstrate; or the at least one of the plurality of cover plate alignmentmarks, of which the orthographic projection on the base substrate isbetween the orthographic projection of the dam glue on the basesubstrate and the cutting region, is at least partially overlapped withthe second inorganic encapsulation layer in the direction perpendicularto the base substrate.
 3. (canceled)
 4. The display panel according toclaim 1, wherein the display substrate comprises a touch structure, thetouch structure is between the encapsulation layer and the opticaladhesive layer in the direction perpendicular to the base substrate, andthe touch structure comprises at least one metal layer, and the at leastone metal layer comprises the plurality of cover plate alignment marks.5. The display panel according to claim 1, wherein a maximum size of anorthographic projection of each of the plurality of cover platealignment marks on the base substrate ranges from 150 microns to 600microns.
 6. The display panel according to claim 1, wherein anorthographic projection of each of the plurality of cover platealignment marks on the base substrate comprises at least one shapeselected from a group consisting of a T shape, a cross shape, and an Lshape.
 7. The display panel according to claim 1, wherein a surface ofthe display substrate directly bearing the plurality of cover platealignment marks is a flat surface.
 8. The display panel according toclaim 1, wherein the frame region comprises a first frame region and asecond frame region which are opposite to each other in a firstdirection; the display panel further comprises a flexible circuit board,and the flexible circuit board is connected with the second frameregion; and the first frame region is provided with the at least one ofthe plurality of cover plate alignment marks located between the damglue and the display region and overlapping with the second inorganicencapsulation layer in the direction perpendicular to the basesubstrate, and/or the second frame region is provided with the at leastone of the plurality of cover plate alignment marks located between thedam glue and the cutting region.
 9. The display panel according to claim8, wherein the frame region further comprises a third frame region and afourth frame region which are opposite to each other in a seconddirection different from the first direction, and the display panelcomprises a curved portion in at least one of the third frame region andthe fourth frame region, and a portion of the cover plate correspondingto the curved portion is curved; the display panel further comprises agate electrode driver in at least one of the third frame region and thefourth frame region; and the plurality of cover plate alignment marksare located outside the third frame region and the fourth frame region.10. The display panel according to claim 8, wherein the plurality ofcover plate alignment marks comprise four cover plate alignment marks,the four cover plate alignment marks are respectively numbered as afirst cover plate alignment mark, a second cover plate alignment mark, athird cover plate alignment mark, and a fourth cover plate alignmentmark in an anticlockwise direction; with respect to an axis parallel tothe first direction, a combination of the first cover plate alignmentmark and the second cover plate alignment mark is symmetrical with acombination of the third cover plate alignment mark and the fourth coverplate alignment mark.
 11. The display panel according to claim 8,wherein the display substrate further comprises an electrode layerextending portion electrically connected with the plurality of lightemitting elements, and the electrode layer extending portion is in theframe region; in the direction perpendicular to the base substrate, theelectrode layer extending portion is between the plurality of coverplate alignment marks and the base substrate; and an orthographicprojection of the electrode layer extending portion on the basesubstrate is overlapped with orthographic projections of the pluralityof cover plate alignment marks on the base substrate.
 12. The displaypanel according to claim 11, wherein the electrode layer extendingportion comprises a first conductive layer and a second conductive layerwhich are stacked, the second conductive layer is on a side of the firstconductive layer away from the base substrate, and the second conductivelayer comprises a portion recessed toward the base substrate, theportion is electrically connected with the first conductive layer, andthe plurality of cover plate alignment marks are in a recessed regiondefined by the portion.
 13. The display panel according to claim 12,wherein the second conductive layer comprises a first sub-conductivelayer, a second sub-conductive layer, and a third sub-conductive layerwhich are sequentially arranged on the base substrate and connected inparallel; and the first sub-conductive layer is between the secondsub-conductive layer and the base substrate in the directionperpendicular to the base substrate.
 14. The display panel according toclaim 13, wherein the display panel further comprises at least oneswitching element, each of the at least one switching element comprisesa gate electrode, a source electrode, and a drain electrode; each of theplurality of light emitting elements comprises a first electrode layerand a second electrode layer, the first sub-conductive layer is in asame layer and made of a same material as the source electrode and drainelectrode, the second sub-conductive layer is in a same layer and madeof a same material as the first electrode layer, and the thirdsub-conductive layer is in a same layer and made of a same material asthe second electrode layer.
 15. The display panel according to claim 8,wherein the second frame region is provided with a circuit boardalignment mark configured for bending the flexible circuit board, and anorthographic projection of the circuit board alignment mark on the basesubstrate is spaced apart from the orthographic projections of theplurality of cover plate alignment marks on the base substrate; and theorthographic projection of the circuit board alignment mark on the basesubstrate has a maximum size, an orthographic projection of each of theplurality of cover plate alignment marks on the base substrate has amaximum size, and the maximum size of the circuit board alignment markis smaller than the maximum size of each of the plurality of cover platealignment marks.
 16. The display panel according to claim 1, wherein thecover plate comprises a window region in the display region and a lightshielding portion located outside the display region; the orthographicprojections of the plurality of cover plate alignment marks on the basesubstrate are in a region where an orthographic projection of the lightshielding portion on the base substrate is located.
 17. The displaypanel according to claim 1, wherein each of the plurality of cover platealignment marks has an integrated structure; and the plurality of coverplate alignment marks are opaque.
 18. The display panel according toclaim 1, wherein a material of the plurality of cover plate alignmentmarks comprises a metal.
 23. 19-23. (canceled)
 24. An alignment method,comprising: irradiating a display substrate and a cover plate forforming a display panel by light, wherein the display panel has adisplay region and a frame region at a periphery of the display region;the display panel comprises the display substrate, the cover plate andan optical adhesive layer connecting the display substrate to the coverplate, the display substrate comprises a plurality of cover platealignment marks, and the cover plate comprises a window portion in thedisplay region and a light shielding portion in the frame region;calculating a center of the display region of the display substrateaccording to the plurality of cover plate alignment marks; calculating acenter of a window portion of the cover plate according to an edge ofthe window portion of the cover plate; and aligning the center of thedisplay region of the display substrate with the center of the windowportion of the cover plate to align the display substrate with the coverplate, wherein the display substrate comprises a flexible base substrateand comprises a plurality of light emitting elements, a pixel defininglayer, and an encapsulation layer, the plurality of light emittingelements, the pixel defining layer, and the encapsulation layer are onthe base substrate, the pixel defining layer separates the plurality oflight emitting elements, and the encapsulation layer is on a side of theplurality of light emitting elements away from the base substrate; theoptical adhesive layer is on a side of the encapsulation layer away fromthe base substrate; the cover plate is on a side of the optical adhesivelayer away from the display substrate; the encapsulation layer comprisesa first inorganic encapsulation layer, a first organic encapsulationlayer, and a second inorganic encapsulation layer which are sequentiallyarranged in a direction away from the base substrate; the frame regioncomprises a dam glue region where an annular dam glue is located and anannular cutting region which is on a side of the dam glue away from thedisplay region; at least one of the plurality of cover plate alignmentmarks is overlapped with the second inorganic encapsulation layer in adirection perpendicular to the base substrate, and an orthographicprojection of the at least one of the plurality of cover plate alignmentmarks on the base substrate is between an orthographic projection of thedam glue on the base substrate and the display region, and/or anorthographic projection of at least one of the plurality of cover platealignment marks on the base substrate is between the orthographicprojection of the dam glue and the cutting region.
 25. A display panel,comprising: a display substrate, comprising a flexible base substrateand comprising a plurality of light emitting elements, a pixel defininglayer, and an encapsulation layer, wherein the plurality of lightemitting elements, the pixel defining layer, and the encapsulation layerare on the base substrate, the pixel defining layer separates theplurality of light emitting elements, and the encapsulation layer is ona side of the plurality of light emitting elements away from the basesubstrate; an optical adhesive layer, on a side of the encapsulationlayer away from the base substrate; and a cover plate, on a side of theoptical adhesive layer away from the display substrate and connectedwith the display substrate through the optical adhesive layer, whereinthe encapsulation layer comprises a first inorganic encapsulation layer,a first organic encapsulation layer, and a second inorganicencapsulation layer which are sequentially arranged in a direction awayfrom the base substrate; and the display substrate further comprises aplurality of cover plate alignment marks configured for aligning thedisplay substrate with the cover plate, and further comprises a touchstructure, the touch structure is between the encapsulation layer andthe optical adhesive layer in a direction perpendicular to the basesubstrate, and the touch structure comprises at least one metal layer,the at least one metal layer comprises the plurality of cover platealignment marks.
 26. The display panel according to claim 25, whereinthe display panel comprises a display region and a frame region at aperiphery of the display region, the frame region comprises a dam glueregion where an annular dam glue is located and an annular cuttingregion on a side of the dam glue away from the display region; at leastone of the plurality of cover plate alignment marks is overlapped withthe second inorganic encapsulation layer in the direction perpendicularto the base substrate, and an orthographic projection of the at leastone of the plurality of cover plate alignment marks on the basesubstrate is between an orthographic projection of the dam glue on thebase substrate and the display region, and/or an orthographic projectionof at least one of the plurality of cover plate alignment marks on thebase substrate is between the orthographic projection of the dam glue onthe base substrate and the cutting region.